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I need assistance with a function in SQL Server 2012 that I created to check for the input value. If the functions detects a numeric - return 0, if detect character return 1.
But I get 2 different result for the same number passing it with quote and without quote.
select dbo.IS_ALIEN('56789')
returns 0
select dbo.IS_ALIEN(56789)
returns 1 (I need to return 0)
This is my function:
ALTER FUNCTION [dbo].[IS_ALIEN]
(#alienNAIC CHAR(1))
RETURNS NUMERIC(10,0)
AS
BEGIN
DECLARE #nNum NUMERIC(1,0);
BEGIN
SET #NnUM = ISNUMERIC(#alienNAIC)
END
BEGIN
IF #nNum = 1
RETURN 0;
END
RETURN 1;
END
Same concept for:
select dbo.IS_ALIEN('AA-11990043')
returns 1
or
select dbo.IS_ALIEN(NULL)
returns 1 (I need it to return 0)
I'm using Oracle function reference (below code is just reference from old database):
create or replace FUNCTION "IS_ALIEN"
( alienNAIC IN char )
RETURN NUMBER IS
nNum number;
BEGIN
SELECT MOD(alienNAIC, 2) into nNum FROM dual;
return 0;
EXCEPTION
WHEN INVALID_NUMBER THEN
return 1;
END;
But T-SQL function doesn't allow make exception of error. So I try to converted as much closer.
I suggest you use something like this (I've trimmed it down somewhat):
ALTER FUNCTION [dbo].[IS_ALIEN](#alienNAIC NVARCHAR(10))
RETURNS INT -- NOTE: You could also return tinyint or bit
AS
BEGIN
IF ISNUMERIC(#alienNAIC) = 1
RETURN 0;
RETURN 1;
END
The trouble with what you were trying is that there's an implicit cast to CHAR(1), the result of which is definitely not numeric as #Joel pointed out:
SELECT CAST(0 As CHAR(1)) -- returns character '0', ISNUMERIC(0) = 1
SELECT CAST(9 As CHAR(1)) -- returns character '9', ISNUMERIC(0) = 1
SELECT CAST(12345 As CHAR(1)) -- any number over 9 returns character '*', ISNUMERIC(12345) = 0
It's an odd implicit casting case I hadn't seen before. By making the parameter an NVARCHAR (assumes possible future double-byte input), strings will be correctly checked and integers passed in will be implicitly cast as NVARCHAR, and the ISNUMERIC check will succeed.
EDIT
Re-reading the question and comments, it looks like you want to identify a particular string syntax to determine if something is an "alien" or not. If you're comfortable changing business logic to fix what apparently is a poor legacy implementation, you could consider something like this instead:
ALTER FUNCTION [dbo].[temp](#alienNAIC NVARCHAR(10))
RETURNS INT -- NOTE: You could also return tinyint or bit
AS
BEGIN
IF #alienNAIC like 'AA-%' AND ISNUMERIC(RIGHT(#alienNAIC, LEN(#alienNAIC) - 3)) = 1
RETURN 1; -- notice this is now 1 instead of 0, we're doing a specific check for 'AA-nnnnn...'
RETURN 0;
END
Note that this should be thoroughly tested against legacy data if it's ever to interact with it - you never know what rubbish data a poorly written legacy system has left behind. Fixing this could well break other things. If you do make this change, document it well.
If you need to check just the first character then you can do like that:
CREATE FUNCTION [dbo].[IS_ALIEN]
(#alienNAIC VARCHAR(200))
RETURNS TINYINT
AS
BEGIN
IF LEFT(#alienNAIC,1) BETWEEN '0' AND '9' RETURN 1;
RETURN 0
END
GO
It seems like you are trying to check whether a string starts with a non-numeric character. Such pattern matches can be performed using LIKE, eg
declare #var nvarchar(10)='A56789'
select
case when #var LIKE '[0-9]%'
then 0 else 1
end AS IsAlien
Returns
1
Both declare #var nvarchar(10)=56789 and declare #var int=56789 return 0 because the number is implicitly converted to a string.
The expression is so short that you probably don't need to convert it to a function. If you do, it could be as simple as :
create FUNCTION [dbo].[IS_ALIEN] (#alienNAIC varchar(200))
RETURNS INT
begin
return case when #alienNAIC LIKE '[0-9]%'
then 0 else 1
end
end
If you want to perform the check in a WHERE clause, just use LIKE, not any function, eg:
WHERE alienNAIC NOT LIKE '[0-9]%'
This particular pattern is just a range search that covers all values between 0 and 9....... The server can use an index that covers the text column to quickly identify the matches. It can't do so when it has to check the result of a function. It will have to calculate the value for every single row before filtering.
I want to determine if a value is integer (like TryParse in .NET). Unfortunatelly ISNUMERIC does not fit me because I want to parse only integers and not every kind of number. Is there such thing as ISINT or something?
Here is some code to make things clear. If MY_FIELD is not int, this code would fail:
SELECT #MY_VAR = CAST(MY_FIELD AS INT)
FROM MY_TABLE
WHERE MY_OTHER_FIELD = 'MY_FILTER'
Thank you
Here's a blog post describing the creation of an IsInteger UDF.
Basically, it recommends adding '.e0' to the value and using IsNumeric. In this way, anything that already had a decimal point now has two decimal points, causing IsNumeric to be false, and anything already expressed in scientific notation is invalidated by the e0.
In his article Can I convert this string to an integer?, Itzik Ben-Gan provides a solution in pure T-SQL and another that uses the CLR.
Which solution should you choose?
Is the T-SQL or CLR Solution Better? The advantage of using the T-SQL
solution is that you don’t need to go outside the domain of T-SQL
programming. However, the CLR solution has two important advantages:
It's simpler and faster. When I tested both solutions against a table
that had 1,000,000 rows, the CLR solution took two seconds, rather
than seven seconds (for the T-SQL solution), to run on my laptop. So
the next time you need to check whether a given string can be
converted to an integer, you can include the T-SQL or CLR solution
that I provided in this article.
If you only want to maintain T-SQL, then use the pure T-SQL solution. If performance is more important than convenience, then use the CLR solution.
The pure T-SQL Solution is tricky. It combines the built-in ISNUMERIC function with pattern-matching and casting to check if the string represents an int.
SELECT keycol, string, ISNUMERIC(string) AS is_numeric,
CASE
WHEN ISNUMERIC(string) = 0 THEN 0
WHEN string LIKE '%[^-+ 0-9]%' THEN 0
WHEN CAST(string AS NUMERIC(38, 0))
NOT BETWEEN -2147483648. AND 2147483647. THEN 0
ELSE 1
END AS is_int
FROM dbo.T1;
The T-SQL part of the CLR solution is simpler. You call the fn_IsInt function just like you would call ISNUMERIC.
SELECT keycol, string, ISNUMERIC(string) AS is_numeric,
dbo.fn_IsInt(string) AS is_int
FROM dbo.T1;
The C# part is simply a wrapper for the .NET's parsing function Int32.TryParse. This works because the SQL Server int and the .NET Int32 are both 32-bit signed integers.
using System;
using System.Data.SqlTypes;
public partial class UserDefinedFunctions
{
[Microsoft.SqlServer.Server.SqlFunction]
public static SqlBoolean fn_IsInt(SqlString s)
{
if (s.IsNull)
return SqlBoolean.False;
else
{
Int32 i = 0;
return Int32.TryParse(s.Value, out i);
}
}
};
Please read Itzik's article for a full explanation of these code samples.
With sqlserver 2005 and later you can use regex-like character classes with LIKE operator. See here.
To check if a string is a non-negative integer (it is a sequence of decimal digits) you can test that it doesn't contain other characters.
SELECT numstr
FROM table
WHERE numstr NOT LIKE '%[^0-9]%'
Note1: This will return empty strings too.
Note2: Using LIKE '%[0-9]%' will return any string that contains at least a digit.
See fiddle
WHERE IsNumeric(MY_FIELD) = 1 AND CAST(MY_FIELD as VARCHAR(5)) NOT LIKE '%.%'
That is probably the simplest solution. Unless your MY_FIELD contains .00 or something of that sort. In which case, cast it to a float to remove any trailing .00s
Necromancing.
As of SQL-Server 2012+, you can use TRY_CAST, which returns NULL if the cast wasn't successful.
Example:
DECLARE #foo varchar(200)
SET #foo = '0123'
-- SET #foo = '-0123'
-- SET #foo = '+0123'
-- SET #foo = '+-0123'
-- SET #foo = '+-0123'
-- SET #foo = '.123'
-- SET #foo = '1.23'
-- SET #foo = '.'
-- SET #foo = '..'
-- SET #foo = '0123e10'
SELECT CASE WHEN TRY_CAST(#foo AS integer) IS NULL AND #foo IS NOT NULL THEN 0 ELSE 1 END AS isInteger
This is the only really reliable way.
Should you need support for SQL-Server 2008, then fall back to Sam DeHaan's answer:
SELECT CASE WHEN ISNUMERIC(#foo + '.e0') = 1 THEN 1 ELSE 0 END AS isInteger
SQL-Server < 2012 (aka 2008R2) will reach end of (extended) support by 2019-07-09.
At this time, which is very soon, support for < 2012 can be dropped.
I wouldn't use any of the other hacks at this point in time anymore.
Just tell your frugal customers to update - it's been over 10 years since 2008.
See whether the below query will help
SELECT *
FROM MY_TABLE
WHERE CHARINDEX('.',MY_FIELD) = 0 AND CHARINDEX(',',MY_FIELD) = 0
AND ISNUMERIC(MY_FIELD) = 1 AND CONVERT(FLOAT,MY_FIELD) / 2147483647 <= 1
The following is correct for a WHERE clause; to make a function wrap it in CASE WHEN.
ISNUMERIC(table.field) > 0 AND PATINDEX('%[^0123456789]%', table.field) = 0
This work around with IsNumeric function will work:
select * from A where ISNUMERIC(x) =1 and X not like '%.%'
or Use
select * from A where x **not like** '%[^0-9]%'
declare #i numeric(28,5) = 12.0001
if (#i/cast(#i as int) > 1)
begin
select 'this is not int'
end
else
begin
select 'this is int'
end
As of SQL Server 2012, the TRY_CONVERT and TRY_CAST functions were implemented. Thise are vast improvements over the ISNUMERIC solution, which can (and does) give false positives (or negatives). For example if you run the below:
SELECT CONVERT(int,V.S)
FROM (VALUES('1'),
('900'),
('hello'),
('12b'),
('1.1'),
('')) V(S)
WHERE ISNUMERIC(V.S) = 1;
Using TRY_CONVERT (or TRY_CAST) avoids that:
SELECT TRY_CONVERT(int,V.S),
V.S,
ISNUMERIC(V.S)
FROM (VALUES('1'),
('900'),
('hello'),
('12b'),
('1.1'),
('')) V(S)
--WHERE TRY_CONVERT(int,V.S) IS NOT NULL; --To filter to only convertable values
Notice that '1.1' returned NULL, which cause the error before (as a string represtation of a decimal cannot be converted to an int) but also that '' returned 0, even though ISNUMERIC states the value "can't be converted".
Use TRY_CONVERT which is an SQL alternative to TryParse in .NET. IsNumeric() isn’t aware that empty strings are counted as (integer)zero, and that some perfectly valid money symbols, by themselves, are not converted to (money)zero. reference
SELECT #MY_VAR = CASE WHEN TRY_CONVERT(INT,MY_FIELD) IS NOT NULL THEN MY_FIELD
ELSE 0
END
FROM MY_TABLE
WHERE MY_OTHER_FIELD = 'MY_FILTER'
I think that there is something wrong with your database design. I think it is a really bad idea to mix varchar and numbers in one column? What is the reason for that?
Of course you can check if there are any chars other than [0-9], but imagine you have a 1m rows in table and your are checking every row. I think it won't work well.
Anyway if you really want to do it I suggest doing it on the client side.
I have a feeling doing it this way is the work of satan, but as an alternative:
How about a TRY - CATCH?
DECLARE #Converted as INT
DECLARE #IsNumeric BIT
BEGIN TRY
SET #Converted = cast(#ValueToCheck as int)
SET #IsNumeric=1
END TRY
BEGIN CATCH
SET #IsNumeric=0
END CATCH
select IIF(#IsNumeric=1,'Integer','Not integer') as IsInteger
This works, though only in SQL Server 2008 and up.
I tried this script and got the answer
ISNUMERIC(Replace(Replace([enter_your_number],'+','A'),'-','A') + '.0e0')
for example for up question this is answer:
SELECT #MY_VAR = CAST(MY_FIELD AS INT)
FROM MY_TABLE
WHERE MY_OTHER_FIELD = 'MY_FILTER' and ISNUMERIC(Replace(Replace(MY_FIELD,'+','A'),'-','A') + '.0e0') = 1
Why not just do something like:
CASE
WHEN ROUND(MY_FIELD,0)=MY_FIELD THEN CAST(MY_FIELD AS INT)
ELSE MY_FIELD
END
as MY_FIELD2
Sometimes you don't get to design the database, you just have to work with what you are given. In my case it's a database located on a computer that I only have read access to which has been around since 2008.
I need to select from a column in a poorly designed database which is a varchar with numbers 1-100 but sometimes a random string. I used the following to get around it (although I wish I could have re designed the entire database).
SELECT A from TABLE where isnumeric(A)=1
I am not a Pro in SQL but what about checking if it is devideable by 1 ?
For me it does the job.
SELECT *
FROM table
WHERE fieldname % 1 = 0
Use PATINDEX
DECLARE #input VARCHAR(10)='102030.40'
SELECT PATINDEX('%[^0-9]%',RTRIM(LTRIM(#input))) AS IsNumber
reference
http://www.intellectsql.com/post-how-to-check-if-the-input-is-numeric/
Had the same question. I finally used
where ATTRIBUTE != round(ATTRIBUTE)
and it worked for me
WHERE IsNumeric(value + 'e0') = 1 AND CONVERT(FLOAT, value) BETWEEN -2147483648 AND 2147483647
Seeing as this is quite old, but my solution isn't here, i thought to add another possible way to do this:
--This query only returns values with decimals
SELECT ActualCost
FROM TransactionHistory
where cast(ActualCost as int) != ActualCost
--This query only returns values without decimals
SELECT ActualCost
FROM TransactionHistory
where cast(ActualCost as int) = ActualCost
The easy part here is checking if the selected value is the same when cast as an integer.
we can check if its a non integer by
SELECT number2
FROM table
WHERE number2 LIKE '%[^0-9]%' and (( right(number2 ,len(number2)-1) LIKE '%[^0-9]%' and lefT(number2 ,1) <> '-') or ( right(number2 ,len(number2)-1) LIKE '%[^0-9]%' and lefT(number2 ,1) in ( '-','+') ) )
DECLARE #zip_code NCHAR(10)
SET #zip_code = '1239'
IF TRY_PARSE( #zip_code AS INT) / TRY_PARSE( #zip_code AS INT) = 1 PRINT 'integer'
ELSE PRINT 'not integer'
This works fine in SQL Server
SELECT (SELECT ISNUMERIC(2) WHERE ISNUMERIC(2)=1 AND 2 NOT LIKE '%.%')
Case
When (LNSEQNBR / 16384)%1 = 0 then 1
else 0
end
I am integrating between 4 data sources:
InternalDeviceRepository
ExternalDeviceRepository
NightlyDeviceDeltas
MidDayDeviceDeltas
Changes flow into the InternalDeviceRepository from the other three sources.
All sources eventually are transformed to have the definition of
FIELDS
=============
IdentityField
Contract
ContractLevel
StartDate
EndDate
ContractStatus
Location
IdentityField is the PrimaryKey, Contract Key is a secondary Key only if a match exists, otherwise a new record needs to be created.
Currently I compare all the fields in a WHERE clause in SQL Statements and also in a number of places in SSIS packages. This creates some unclean looking SQL and SSIS packages.
I've been mulling computing a hash of ContractLevel, StartDate, EndDate, ContractStatus, and Location and adding that to each of the input tables. This would allow me to use a single value for comparison, instead of 5 separate ones each time.
I've never done this before, nor have I seen it done. Is there a reason that it should be used, or is that a cleaner way to do it?
It is a valid approach. Consider to introduce a calculated field with the hash and index on it.
You may use either CHECKSUM function or write your own hash function like this:
CREATE FUNCTION dbo.GetMyLongHash(#data VARBINARY(MAX))
RETURNS VARBINARY(MAX)
WITH RETURNS NULL ON NULL INPUT
AS
BEGIN
DECLARE #res VARBINARY(MAX) = 0x
DECLARE #position INT = 1, #len INT = DATALENGTH(#data)
WHILE 1 = 1
BEGIN
SET #res = #res + HASHBYTES('MD5', SUBSTRING(#data, #position, 8000))
SET #position = #position+8000
IF #Position > #len
BREAK
END
WHILE DATALENGTH(#res) > 16 SET #res= dbo.GetMyLongHash(#res)
RETURN #res
END
which will give you 16-byte value - you may take all the 16 bytes as Guid, or only first 8-bytes as bigint and compare it.
Adapt the function in your way - to accept string as parameter or even all the your fields instead of varbinary
BUT
be careful with strings casing, datetime formats
if using CHECKSUM - check also other fields, checksum produces dublicates
avoid using 4-byte hash result on relaively big table
I have some dirty input data that is being imported into a raw source table within SQL Server (2008 R2). Fields that are defined as decimal(9,2) or decimal(4,2) by the input provider are coming in as strings, however, the strings do not always conform to the data definition (go figure!).
We import the data from flat files into the raw tables,then apply some conversion scripts to insert the 'cleaned' data into tables with the proper data types assigned to columns.
For instance:
raw_table
TotalAmount varchar(12)
clean_table
TotalAmount decimal(9,2)
Now, my question is this. If I want to do some 'basic' cleanup on this, I would want to do it in a function along the lines of:
CREATE FUNCTION [dbo].[StringToDecimal]
(
#conversionString VARCHAR(12)
)
RETURNS DECIMAL(9,2)
AS
BEGIN
DECLARE #rsp DECIMAL(9,2)
IF ISNUMERIC( LTRIM(RTRIM(REPLACE(#conversionString,' ',''))) ) = 1
BEGIN
SET #rsp = ISNULL( CONVERT( decimal(17,6), NULLIF( LTRIM(RTRIM(REPLACE(#conversionString,' ',''))),'') ), 0 )
END
ELSE
BEGIN
SET #rsp = 0 -- or we can return NULL here
END
RETURN #rsp
END
However, how could one go about supporting various sized decimals in this mix? Is there a way to parametrize the response type? I considered just returning a decimal of the largest size we generally see, then converting it again on the other end, however, you run into arithmetic overflow issues.
Would appreciate any thoughts/insight into solving this one!
Is there a way to parametrize the response type?
It's simpler than you think. Just return as a VARCHAR and do the casting to decimal(x,y) from the VARCHAR. You don't even need to cast - you can directly assign a VARCHAR (as long as it holds valid decimal data) to a decimal column/variable.
I will create 2 functions instead. StringToDecimal2 does the actual conversion, but returns one of 6 "error codes". You can use it to check why a string is invalid. Or use the wrapper dbo.StringToDecimal which just turns the invalid codes into NULL.
CREATE FUNCTION [dbo].[StringToDecimal2]
(
#conversionString VARCHAR(12),
#precision int, -- total digits
#scale int -- after decimal point
)
RETURNS VARCHAR(100)
AS
BEGIN
-- remove spaces, we'll allow this error. no need to trim
set #conversionString = REPLACE(#conversionString,' ','')
-- note: 1,234.56 (thousands separated) will be invalid, so will 1,234,56 (European decimals)
-- well, ok, let's clean up the thousands separators. BUT! It will incorrectly scale European decimals
set #conversionString = REPLACE(#conversionString,',','')
-- we don't support scientific notation either, so 1e4 (10,000) is out
if #conversionString like '%[^0-9.+-]%' return 'INVALID1' -- only digits and decimal are valid (plus +-)
if #conversionString like '%.%.%' return 'INVALID2' -- too many decimals
if #conversionString like '_%[+-]%' return 'INVALID3' -- +- symbol not in the first position
if #conversionString like '[.+-]' return 'INVALID4' -- a single character from "+-."
if #conversionString like '[+-].' return 'INVALID5' -- symbol and decimal only
-- add a decimal place so it is easier to work with below
if #conversionString not like '%.%'
set #conversionString = #conversionString + '.'
-- allow decimal places to go only as far as scale
set #conversionString = left(#conversionString, charindex('.', #conversionString)+#scale)
-- ensure the data is within precision number of digits in total
if charindex('.', #conversionString) > #precision - #scale + 1
return 'INVALID6' -- too many digits before decimal
RETURN #conversionString
END
GO
CREATE FUNCTION [dbo].[StringToDecimal]
(
#conversionString VARCHAR(12),
#precision int, -- total digits
#scale int -- after decimal point
)
RETURNS VARCHAR(100)
AS
BEGIN
RETURN case when [dbo].[StringToDecimal2](#conversionString, #precision, #scale) like 'INVALID%'
then null else [dbo].[StringToDecimal2](#conversionString, #precision, #scale) end
END
GO
Some tests:
select [dbo].[StringToDecimal2]('12342342', 9,2)
select convert(decimal(9,2),[dbo].[StringToDecimal]('1234234', 9,2))
select convert(decimal(9,2),[dbo].[StringToDecimal]('12342342', 9,2))
select convert(decimal(9,2),[dbo].[StringToDecimal]('123423.3333', 9,2))
select convert(decimal(20,10),[dbo].[StringToDecimal]('123423sd.3333', 20,10))
select convert(decimal(20,10),[dbo].[StringToDecimal]('123423sd..3333', 20,10))
select convert(decimal(20,10),[dbo].[StringToDecimal]('-123423.3333', 20,10))
select convert(decimal(20,10),[dbo].[StringToDecimal]('+123423..3333', 20,10))
Thanks for the extra information. It sounds like you have three steps:
Remove all characters from the string that are not digits or a decimal point (do you ever get multiple points in one string?)
Convert to (9,5) or (4,1) as appropriate (how do you decide this? is there rounding? does 10X.781 become 10.78100 or 10.7 or 10.8?)
Insert/update the final value somewhere
Based on point 1 alone, I would immediately avoid TSQL and think about an external script or CLR procedure. A CLR function could do the parsing, but you still have the problem of returning different data types.
Since this appears to be some kind of ETL task, in my environment I would probably implement it as a script component in an SSIS package. The component would do the parsing and send the clean data to different outputs for further processing. If it was a one-time task I would use a Python script to parse the input data and generate INSERT or UPDATE statements.
I don't know if any of those solutions are suitable for you, but maybe it'll give you some ideas. And you should probably avoid the ISNUMERIC() function; search this site or Google to find some of the 'strange' input that it considers to be numeric.
Is there a straightforward way of finding the index of the last occurrence of a string using SQL? I am using SQL Server 2000 right now. I basically need the functionality that the .NET System.String.LastIndexOf method provides. A little googling revealed this - Function To Retrieve Last Index - but that does not work if you pass in a "text" column expression. Other solutions found elsewhere work only so long as the text you are searching for is 1 character long.
I will probably have to cook a function up. If I do so, I will post it here so you folks can look at it and maybe make use of.
Straightforward way? No, but I've used the reverse. Literally.
In prior routines, to find the last occurence of a given string, I used the REVERSE() function, followed CHARINDEX, followed again by REVERSE to restore the original order. For instance:
SELECT
mf.name
,mf.physical_name
,reverse(left(reverse(physical_name), charindex('\', reverse(physical_name)) -1))
from sys.master_files mf
shows how to extract the actual database file names from from their "physical names", no matter how deeply nested in subfolders. This does search for only one character (the backslash), but you can build on this for longer search strings.
The only downside is, I don't know how well this will work on TEXT data types. I've been on SQL 2005 for a few years now, and am no longer conversant with working with TEXT -- but I seem to recall you could use LEFT and RIGHT on it?
Philip
The simplest way is....
REVERSE(SUBSTRING(REVERSE([field]),0,CHARINDEX('[expr]',REVERSE([field]))))
If you are using Sqlserver 2005 or above, using REVERSE function many times is detrimental to performance, below code is more efficient.
DECLARE #FilePath VARCHAR(50) = 'My\Super\Long\String\With\Long\Words'
DECLARE #FindChar VARCHAR(1) = '\'
-- text before last slash
SELECT LEFT(#FilePath, LEN(#FilePath) - CHARINDEX(#FindChar,REVERSE(#FilePath))) AS Before
-- text after last slash
SELECT RIGHT(#FilePath, CHARINDEX(#FindChar,REVERSE(#FilePath))-1) AS After
-- the position of the last slash
SELECT LEN(#FilePath) - CHARINDEX(#FindChar,REVERSE(#FilePath)) + 1 AS LastOccuredAt
You are limited to small list of functions for text data type.
All I can suggest is start with PATINDEX, but work backwards from DATALENGTH-1, DATALENGTH-2, DATALENGTH-3 etc until you get a result or end up at zero (DATALENGTH-DATALENGTH)
This really is something that SQL Server 2000 simply can't handle.
Edit for other answers : REVERSE is not on the list of functions that can be used with text data in SQL Server 2000
DECLARE #FilePath VARCHAR(50) = 'My\Super\Long\String\With\Long\Words'
DECLARE #FindChar VARCHAR(1) = '\'
SELECT LEN(#FilePath) - CHARINDEX(#FindChar,REVERSE(#FilePath)) AS LastOccuredAt
Old but still valid question, so heres what I created based on the info provided by others here.
create function fnLastIndexOf(#text varChar(max),#char varchar(1))
returns int
as
begin
return len(#text) - charindex(#char, reverse(#text)) -1
end
REVERSE(SUBSTRING(REVERSE(ap_description),CHARINDEX('.',REVERSE(ap_description)),len(ap_description)))
worked better for me
This worked very well for me.
REVERSE(SUBSTRING(REVERSE([field]), CHARINDEX(REVERSE('[expr]'), REVERSE([field])) + DATALENGTH('[expr]'), DATALENGTH([field])))
Hmm, I know this is an old thread, but a tally table could do this in SQL2000 (or any other database):
DECLARE #str CHAR(21),
#delim CHAR(1)
SELECT #str = 'Your-delimited-string',
#delim = '-'
SELECT
MAX(n) As 'position'
FROM
dbo._Tally
WHERE
substring(#str, _Tally.n, 1) = #delim
A tally table is just a table of incrementing numbers.
The substring(#str, _Tally.n, 1) = #delim gets the position of each delimiter, then you just get the maximum position in that set.
Tally tables are awesome. If you haven't used them before, there is a good article on SQL Server Central.
*EDIT: Removed n <= LEN(TEXT_FIELD), as you can't use LEN() on the TEXT type. As long as the substring(...) = #delim remains though the result is still correct.
This answer uses MS SQL Server 2008 (I don't have access to MS SQL Server 2000), but the way I see it according to the OP are 3 situations to take into consideration. From what I've tried no answer here covers all 3 of them:
Return the last index of a search character in a given string.
Return the last index of a search sub-string (more than just a single
character) in a given string.
If the search character or sub-string is not in the given string return 0
The function I came up with takes 2 parameters:
#String NVARCHAR(MAX) : The string to be searched
#FindString NVARCHAR(MAX) : Either a single character or a sub-string to get the last
index of in #String
It returns an INT that is either the positive index of #FindString in #String or 0 meaning that #FindString is not in #String
Here's an explanation of what the function does:
Initializes #ReturnVal to 0 indicating that #FindString is not in #String
Checks the index of the #FindString in #String by using CHARINDEX()
If the index of #FindString in #String is 0, #ReturnVal is left as 0
If the index of #FindString in #String is > 0, #FindString is in #String so
it calculates the last index of #FindString in #String by using REVERSE()
Returns #ReturnVal which is either a positive number that is the last index of
#FindString in #String or 0 indicating that #FindString is not in #String
Here's the create function script (copy and paste ready):
CREATE FUNCTION [dbo].[fn_LastIndexOf]
(#String NVARCHAR(MAX)
, #FindString NVARCHAR(MAX))
RETURNS INT
AS
BEGIN
DECLARE #ReturnVal INT = 0
IF CHARINDEX(#FindString,#String) > 0
SET #ReturnVal = (SELECT LEN(#String) -
(CHARINDEX(REVERSE(#FindString),REVERSE(#String)) +
LEN(#FindString)) + 2)
RETURN #ReturnVal
END
Here's a little bit that conveniently tests the function:
DECLARE #TestString NVARCHAR(MAX) = 'My_sub2_Super_sub_Long_sub1_String_sub_With_sub_Long_sub_Words_sub2_'
, #TestFindString NVARCHAR(MAX) = 'sub'
SELECT dbo.fn_LastIndexOf(#TestString,#TestFindString)
I have only run this on MS SQL Server 2008 because I don't have access to any other version but from what I've looked into this should be good for 2008+ at least.
Enjoy.
Reverse both your string and your substring, then search for the first occurrence.
If you want to get the index of the last space in a string of words, you can use this expression
RIGHT(name, (CHARINDEX(' ',REVERSE(name),0)) to return the last word in the string. This is helpful if you want to parse out the last name of a full name that includes initials for the first and /or middle name.
Some of the other answers return an actual string whereas I had more need to know the actual index int. And the answers that do that seem to over-complicate things. Using some of the other answers as inspiration, I did the following...
First, I created a function:
CREATE FUNCTION [dbo].[LastIndexOf] (#stringToFind varchar(max), #stringToSearch varchar(max))
RETURNS INT
AS
BEGIN
RETURN (LEN(#stringToSearch) - CHARINDEX(#stringToFind,REVERSE(#stringToSearch))) + 1
END
GO
Then, in your query you can simply do this:
declare #stringToSearch varchar(max) = 'SomeText: SomeMoreText: SomeLastText'
select dbo.LastIndexOf(':', #stringToSearch)
The above should return 23 (the last index of ':')
Hope this made it a little easier for someone!
I realize this is a several years old question, but...
On Access 2010, you can use InStrRev() to do this. Hope this helps.
I know that it will be inefficient but have you considered casting the text field to varchar so that you can use the solution provided by the website you found? I know that this solution would create issues as you could potentially truncate the record if the length in the text field overflowed the length of your varchar (not to mention it would not be very performant).
Since your data is inside a text field (and you are using SQL Server 2000) your options are limited.
#indexOf = <whatever characters you are searching for in your string>
#LastIndexOf = LEN([MyField]) - CHARINDEX(#indexOf, REVERSE([MyField]))
Haven't tested, it might be off by one because of zero index, but works in SUBSTRING function when chopping off from #indexOf characters to end of your string
SUBSTRING([MyField], 0, #LastIndexOf)
This code works even if the substring contains more than 1 character.
DECLARE #FilePath VARCHAR(100) = 'My_sub_Super_sub_Long_sub_String_sub_With_sub_Long_sub_Words'
DECLARE #FindSubstring VARCHAR(5) = '_sub_'
-- Shows text before last substing
SELECT LEFT(#FilePath, LEN(#FilePath) - CHARINDEX(REVERSE(#FindSubstring), REVERSE(#FilePath)) - LEN(#FindSubstring) + 1) AS Before
-- Shows text after last substing
SELECT RIGHT(#FilePath, CHARINDEX(REVERSE(#FindSubstring), REVERSE(#FilePath)) -1) AS After
-- Shows the position of the last substing
SELECT LEN(#FilePath) - CHARINDEX(REVERSE(#FindSubstring), REVERSE(#FilePath)) AS LastOccuredAt
I needed to find the nth last position of a backslash in a folder path.
Here is my solution.
/*
http://stackoverflow.com/questions/1024978/find-index-of-last-occurrence-of-a-sub-string-using-t-sql/30904809#30904809
DROP FUNCTION dbo.GetLastIndexOf
*/
CREATE FUNCTION dbo.GetLastIndexOf
(
#expressionToFind VARCHAR(MAX)
,#expressionToSearch VARCHAR(8000)
,#Occurrence INT = 1 -- Find the nth last
)
RETURNS INT
AS
BEGIN
SELECT #expressionToSearch = REVERSE(#expressionToSearch)
DECLARE #LastIndexOf INT = 0
,#IndexOfPartial INT = -1
,#OriginalLength INT = LEN(#expressionToSearch)
,#Iteration INT = 0
WHILE (1 = 1) -- Poor man's do-while
BEGIN
SELECT #IndexOfPartial = CHARINDEX(#expressionToFind, #expressionToSearch)
IF (#IndexOfPartial = 0)
BEGIN
IF (#Iteration = 0) -- Need to compensate for dropping out early
BEGIN
SELECT #LastIndexOf = #OriginalLength + 1
END
BREAK;
END
IF (#Occurrence > 0)
BEGIN
SELECT #expressionToSearch = SUBSTRING(#expressionToSearch, #IndexOfPartial + 1, LEN(#expressionToSearch) - #IndexOfPartial - 1)
END
SELECT #LastIndexOf = #LastIndexOf + #IndexOfPartial
,#Occurrence = #Occurrence - 1
,#Iteration = #Iteration + 1
IF (#Occurrence = 0) BREAK;
END
SELECT #LastIndexOf = #OriginalLength - #LastIndexOf + 1 -- Invert due to reverse
RETURN #LastIndexOf
END
GO
GRANT EXECUTE ON GetLastIndexOf TO public
GO
Here are my test cases which pass
SELECT dbo.GetLastIndexOf('f','123456789\123456789\', 1) as indexOf -- expect 0 (no instances)
SELECT dbo.GetLastIndexOf('\','123456789\123456789\', 1) as indexOf -- expect 20
SELECT dbo.GetLastIndexOf('\','123456789\123456789\', 2) as indexOf -- expect 10
SELECT dbo.GetLastIndexOf('\','1234\6789\123456789\', 3) as indexOf -- expect 5
To get the part before the last occurence of the delimiter (works only for NVARCHAR due to DATALENGTH usage):
DECLARE #Fullstring NVARCHAR(30) = '12.345.67890.ABC';
DECLARE #Delimiter CHAR(1) = '.';
SELECT SUBSTRING(#Fullstring, 1, DATALENGTH(#Fullstring)/2 - CHARINDEX(#Delimiter, REVERSE(#Fullstring)));
This answer meets the requirements of the OP. specifically it allows the needle to be more than a single character and it does not generate an error when needle is not found in haystack. It seemed to me that most (all?) of the other answers did not handle those edge cases. Beyond that I added the "Starting Position" argument provided by the native MS SQL server CharIndex function. I tried to exactly mirror the specification for CharIndex except to process right to left instead of left to right. eg I return null if either needle or haystack is null and I return zero if needle is not found in haystack. One thing that I could not get around is that with the built in function the third parameter is optional. With SQL Server user defined functions, all parameters must be provided in the call unless the function is called using "EXEC" . While the third parameter must be included in the parameter list, you can provide the keyword "default" as a placeholder for it without having to give it a value (see examples below). Since it is easier to remove the third parameter from this function if not desired than it would be to add it if needed I have included it here as a starting point.
create function dbo.lastCharIndex(
#needle as varchar(max),
#haystack as varchar(max),
#offset as bigint=1
) returns bigint as begin
declare #position as bigint
if #needle is null or #haystack is null return null
set #position=charindex(reverse(#needle),reverse(#haystack),#offset)
if #position=0 return 0
return (len(#haystack)-(#position+len(#needle)-1))+1
end
go
select dbo.lastCharIndex('xyz','SQL SERVER 2000 USES ANSI SQL',default) -- returns 0
select dbo.lastCharIndex('SQL','SQL SERVER 2000 USES ANSI SQL',default) -- returns 27
select dbo.lastCharIndex('SQL','SQL SERVER 2000 USES ANSI SQL',1) -- returns 27
select dbo.lastCharIndex('SQL','SQL SERVER 2000 USES ANSI SQL',11) -- returns 1
I came across this thread while searching for a solution to my similar problem which had the exact same requirement but was for a different kind of database that was also lacking the REVERSE function.
In my case this was for a OpenEdge (Progress) database, which has a slightly different syntax. This made the INSTR function available to me that most Oracle typed databases offer.
So I came up with the following code:
SELECT
INSTR(foo.filepath, '/',1, LENGTH(foo.filepath) - LENGTH( REPLACE( foo.filepath, '/', ''))) AS IndexOfLastSlash
FROM foo
However, for my specific situation (being the OpenEdge (Progress) database) this did not result into the desired behaviour because replacing the character with an empty char gave the same length as the original string. This doesn't make much sense to me but I was able to bypass the problem with the code below:
SELECT
INSTR(foo.filepath, '/',1, LENGTH( REPLACE( foo.filepath, '/', 'XX')) - LENGTH(foo.filepath)) AS IndexOfLastSlash
FROM foo
Now I understand that this code won't solve the problem for T-SQL because there is no alternative to the INSTR function that offers the Occurence property.
Just to be thorough I'll add the code needed to create this scalar function so it can be used the same way like I did in the above examples.
-- Drop the function if it already exists
IF OBJECT_ID('INSTR', 'FN') IS NOT NULL
DROP FUNCTION INSTR
GO
-- User-defined function to implement Oracle INSTR in SQL Server
CREATE FUNCTION INSTR (#str VARCHAR(8000), #substr VARCHAR(255), #start INT, #occurrence INT)
RETURNS INT
AS
BEGIN
DECLARE #found INT = #occurrence,
#pos INT = #start;
WHILE 1=1
BEGIN
-- Find the next occurrence
SET #pos = CHARINDEX(#substr, #str, #pos);
-- Nothing found
IF #pos IS NULL OR #pos = 0
RETURN #pos;
-- The required occurrence found
IF #found = 1
BREAK;
-- Prepare to find another one occurrence
SET #found = #found - 1;
SET #pos = #pos + 1;
END
RETURN #pos;
END
GO
To avoid the obvious, when the REVERSE function is available you do not need to create this scalar function and you can just get the required result like this:
SELECT
LEN(foo.filepath) - CHARINDEX('/', REVERSE(foo.filepath))+1 AS LastIndexOfSlash
FROM foo
handles lookinng for something > 1 char long.
feel free to increase the parm sizes if you like.
couldnt resist posting
drop function if exists lastIndexOf
go
create function lastIndexOf(#searchFor varchar(100),#searchIn varchar(500))
returns int
as
begin
if LEN(#searchfor) > LEN(#searchin) return 0
declare #r varchar(500), #rsp varchar(100)
select #r = REVERSE(#searchin)
select #rsp = REVERSE(#searchfor)
return len(#searchin) - charindex(#rsp, #r) - len(#searchfor)+1
end
and tests
select dbo.lastIndexof('greg','greg greg asdflk; greg sadf' ) -- 18
select dbo.lastIndexof('greg','greg greg asdflk; grewg sadf' ) --5
select dbo.lastIndexof(' ','greg greg asdflk; grewg sadf' ) --24
This thread has been going for a while. I'll offer a solution covering different basis with example:
declare #aStringData varchar(100) = 'The quick brown/fox jumps/over the/lazy dog.pdf'
/*
The quick brown/fox jumps/over the/lazy dog.pdf
fdp.god yzal/eht revo/spmuj xof/nworb kciuq ehT
*/
select
Len(#aStringData) - CharIndex('/', Reverse(#aStringData)) + 1 [Char Index],
-- Get left side of character, without the character '/'
Left(#aStringData, Len(#aStringData) - CharIndex('/', Reverse(#aStringData))) [Left excluding char],
-- Get left side of character, including the character '/'
Left(#aStringData, Len(#aStringData) - CharIndex('/', Reverse(#aStringData)) + 1) [Left including char],
-- Get right side of character, without the character '/'
Right(#aStringData, CharIndex('/', Reverse(#aStringData)) - 1) [Right including char]
To get char position, need to reverse the string as CharIndex gets the first occurrence. Remembering as we're reversing, the CharIndex cursor will land on the other side of the character we're finding. So expect to compensate by -1 or +1, depending if wanting to get left or right side portion of string.