Select with Left Function Condition SQL Server [duplicate] - sql-server
I've been using this for some time:
SUBSTRING(str_col, PATINDEX('%[^0]%', str_col), LEN(str_col))
However recently, I've found a problem with columns with all "0" characters like '00000000' because it never finds a non-"0" character to match.
An alternative technique I've seen is to use TRIM:
REPLACE(LTRIM(REPLACE(str_col, '0', ' ')), ' ', '0')
This has a problem if there are embedded spaces, because they will be turned into "0"s when the spaces are turned back into "0"s.
I'm trying to avoid a scalar UDF. I've found a lot of performance problems with UDFs in SQL Server 2005.
SUBSTRING(str_col, PATINDEX('%[^0]%', str_col+'.'), LEN(str_col))
Why don't you just cast the value to INTEGER and then back to VARCHAR?
SELECT CAST(CAST('000000000' AS INTEGER) AS VARCHAR)
--------
0
Other answers here to not take into consideration if you have all-zero's (or even a single zero).
Some always default an empty string to zero, which is wrong when it is supposed to remain blank.
Re-read the original question. This answers what the Questioner wants.
Solution #1:
--This example uses both Leading and Trailing zero's.
--Avoid losing those Trailing zero's and converting embedded spaces into more zeros.
--I added a non-whitespace character ("_") to retain trailing zero's after calling Replace().
--Simply remove the RTrim() function call if you want to preserve trailing spaces.
--If you treat zero's and empty-strings as the same thing for your application,
-- then you may skip the Case-Statement entirely and just use CN.CleanNumber .
DECLARE #WackadooNumber VarChar(50) = ' 0 0123ABC D0 '--'000'--
SELECT WN.WackadooNumber, CN.CleanNumber,
(CASE WHEN WN.WackadooNumber LIKE '%0%' AND CN.CleanNumber = '' THEN '0' ELSE CN.CleanNumber END)[AllowZero]
FROM (SELECT #WackadooNumber[WackadooNumber]) AS WN
OUTER APPLY (SELECT RTRIM(RIGHT(WN.WackadooNumber, LEN(LTRIM(REPLACE(WN.WackadooNumber + '_', '0', ' '))) - 1))[CleanNumber]) AS CN
--Result: "123ABC D0"
Solution #2 (with sample data):
SELECT O.Type, O.Value, Parsed.Value[WrongValue],
(CASE WHEN CHARINDEX('0', T.Value) > 0--If there's at least one zero.
AND LEN(Parsed.Value) = 0--And the trimmed length is zero.
THEN '0' ELSE Parsed.Value END)[FinalValue],
(CASE WHEN CHARINDEX('0', T.Value) > 0--If there's at least one zero.
AND LEN(Parsed.TrimmedValue) = 0--And the trimmed length is zero.
THEN '0' ELSE LTRIM(RTRIM(Parsed.TrimmedValue)) END)[FinalTrimmedValue]
FROM
(
VALUES ('Null', NULL), ('EmptyString', ''),
('Zero', '0'), ('Zero', '0000'), ('Zero', '000.000'),
('Spaces', ' 0 A B C '), ('Number', '000123'),
('AlphaNum', '000ABC123'), ('NoZero', 'NoZerosHere')
) AS O(Type, Value)--O is for Original.
CROSS APPLY
( --This Step is Optional. Use if you also want to remove leading spaces.
SELECT LTRIM(RTRIM(O.Value))[Value]
) AS T--T is for Trimmed.
CROSS APPLY
( --From #CadeRoux's Post.
SELECT SUBSTRING(O.Value, PATINDEX('%[^0]%', O.Value + '.'), LEN(O.Value))[Value],
SUBSTRING(T.Value, PATINDEX('%[^0]%', T.Value + '.'), LEN(T.Value))[TrimmedValue]
) AS Parsed
Results:
Summary:
You could use what I have above for a one-off removal of leading-zero's.
If you plan on reusing it a lot, then place it in an Inline-Table-Valued-Function (ITVF).
Your concerns about performance problems with UDF's is understandable.
However, this problem only applies to All-Scalar-Functions and Multi-Statement-Table-Functions.
Using ITVF's is perfectly fine.
I have the same problem with our 3rd-Party database.
With Alpha-Numeric fields many are entered in without the leading spaces, dang humans!
This makes joins impossible without cleaning up the missing leading-zeros.
Conclusion:
Instead of removing the leading-zeros, you may want to consider just padding your trimmed-values with leading-zeros when you do your joins.
Better yet, clean up your data in the table by adding leading zeros, then rebuilding your indexes.
I think this would be WAY faster and less complex.
SELECT RIGHT('0000000000' + LTRIM(RTRIM(NULLIF(' 0A10 ', ''))), 10)--0000000A10
SELECT RIGHT('0000000000' + LTRIM(RTRIM(NULLIF('', ''))), 10)--NULL --When Blank.
Instead of a space replace the 0's with a 'rare' whitespace character that shouldn't normally be in the column's text. A line feed is probably good enough for a column like this. Then you can LTrim normally and replace the special character with 0's again.
My version of this is an adaptation of Arvo's work, with a little more added on to ensure two other cases.
1) If we have all 0s, we should return the digit 0.
2) If we have a blank, we should still return a blank character.
CASE
WHEN PATINDEX('%[^0]%', str_col + '.') > LEN(str_col) THEN RIGHT(str_col, 1)
ELSE SUBSTRING(str_col, PATINDEX('%[^0]%', str_col + '.'), LEN(str_col))
END
The following will return '0' if the string consists entirely of zeros:
CASE WHEN SUBSTRING(str_col, PATINDEX('%[^0]%', str_col+'.'), LEN(str_col)) = '' THEN '0' ELSE SUBSTRING(str_col, PATINDEX('%[^0]%', str_col+'.'), LEN(str_col)) END AS str_col
This makes a nice Function....
DROP FUNCTION [dbo].[FN_StripLeading]
GO
CREATE FUNCTION [dbo].[FN_StripLeading] (#string VarChar(128), #stripChar VarChar(1))
RETURNS VarChar(128)
AS
BEGIN
-- http://stackoverflow.com/questions/662383/better-techniques-for-trimming-leading-zeros-in-sql-server
DECLARE #retVal VarChar(128),
#pattern varChar(10)
SELECT #pattern = '%[^'+#stripChar+']%'
SELECT #retVal = CASE WHEN SUBSTRING(#string, PATINDEX(#pattern, #string+'.'), LEN(#string)) = '' THEN #stripChar ELSE SUBSTRING(#string, PATINDEX(#pattern, #string+'.'), LEN(#string)) END
RETURN (#retVal)
END
GO
GRANT EXECUTE ON [dbo].[FN_StripLeading] TO PUBLIC
cast(value as int) will always work if string is a number
SELECT CAST(CAST('000000000' AS INTEGER) AS VARCHAR)
This has a limit on the length of the string that can be converted to an INT
If you are using Snowflake SQL, might use this:
ltrim(str_col,'0')
The ltrim function removes all instances of the designated set of characters from the left side.
So ltrim(str_col,'0') on '00000008A' would return '8A'
And rtrim(str_col,'0.') on '$125.00' would return '$125'
This might help
SELECT ABS(column_name) FROM [db].[schema].[table]
replace(ltrim(replace(Fieldname.TableName, '0', '')), '', '0')
The suggestion from Thomas G worked for our needs.
The field in our case was already string and only the leading zeros needed to be trimmed. Mostly it's all numeric but sometimes there are letters so the previous INT conversion would crash.
For converting number as varchar to int, you could also use simple
(column + 0)
Very easy way, when you just work with numeric values:
SELECT
TRY_CONVERT(INT, '000053830')
Try this:
replace(ltrim(replace(#str, '0', ' ')), ' ', '0')
If you do not want to convert into int, I prefer this below logic because it can handle nulls
IFNULL(field,LTRIM(field,'0'))
SUBSTRING(str_col, IIF(LEN(str_col) > 0, PATINDEX('%[^0]%', LEFT(str_col, LEN(str_col) - 1) + '.'), 0), LEN(str_col))
Works fine even with '0', '00' and so on.
Starting with SQL Server 2022 (16.x) you can do this
TRIM ( [ LEADING | TRAILING | BOTH ] [characters FROM ] string )
In MySQL you can do this...
Trim(Leading '0' from your_column)
Related
SQL Server - remove left part of string before a specific character
I have a VARCHAR value that looks like this: 5.95 $ Additional fees How can I remove everything left from character '$' (including that character) ? So that I get the following result: Additional fees The '$' is always present.
STUFF and CHARINDEX would be the simpliest way, in my opinion:
SELECT STUFF(YourColumn,1, CHARINDEX('$',YourColumn),'')
FROM (VALUES('5.95 $ Additional fees'))V(YourColumn);
Note that as $ has a whitespace afterwards, the value returned will have a leading whitespace (' Additional fees'). You could use TRIM (or LTRIM and RTRIM on older versions of SQL Server) to remove this, if it isn't wanted.
I haven't assumed that the portion string to be replaced is CHARINDEX('$',YourColumn)+1, as we have one sample. As far as we know, you could also have values such as '10.99$Base Cost'. If the +1 was used, it would return 'ase Cost' for such a value.
Hello do it like below syntax
declare #temp nvarchar(max)='5.95 $ Additional fees'
select SUBSTRING(#temp,charindex('$',#temp)+1,len(#temp)-1)
You can use SUBSTRING get the particular string and CHARINDEX function to get index of special character, in your case $.
DECLARE #Var VARCHAR(100)
SET #Var = '5.95 $ Additional fees'
SELECT SUBSTRING(#Var, CHARINDEX('$', #Var) + 1, LEN(#Var) - LEN(LEFT(#Var, CHARINDEX('$', #Var))))
Why does LEN( char(32) ) = 0 in T-SQL?
I wanted to write a function to count the number of delimiters or any substring (which could be a space) in a string of text, throwing a hack error if the delimiter was null or empty:
if len(#lookfor)=0 or #lookfor is null return Cast('substring must not be null or empty' as int)
But if the function is called with #lookfor = ' ' that trips the error.
I am aware of DATALENGTH(). Just curious why a single space is treated as "trailing" if there's nothing before it.
I am aware of DATALENGTH(). Just curious why a single space is treated
as "trailing" if there's nothing before it.
It's trailing because it's at the end of the string. It's also leading since it's the at the beginning.
But if the function is called with #lookfor = '' that trips the error
Something that messes a lot of people up with SQL is how '' = ' '; Note this query:
DECLARE #blank VARCHAR(10) = '', #space VARCHAR(10) = CHAR(32);
SELECT CASE WHEN #blank = #space THEN 'That the...!?!?' END;
You can change #space to CHAR(32)+CHAR(32)+.... and #space and #blank will still be equal.
Complicating things a little more note that the DATALENGTH for a blank/empty value is 0 when it's a VARCHAR(N) but the DATALENGTH is N when for CHAR(N) values. In other words,
SELECT DATALENGTH(CAST('' AS CHAR(1))) returns 1 and SELECT DATALENGTH(CAST('' AS CHAR(10))) returns 10.
That means that if your delimiter variable is say, CHAR(1) - that will mess you up. Here's the function for you:
CREATE FUNCTION dbo.CountDelimiters(#string VARCHAR(8000), #delimiter VARCHAR(1))
RETURNS TABLE WITH SCHEMABINDING AS RETURN
SELECT DCount = MAX(DATALENGTH(#string)-LEN(REPLACE(#string,#delimiter,'')))
WHERE DATALENGTH(#delimiter) > 0;
Note that #delimter is VARCHAR(1) and NOT a CHAR datatype.
The formula to count delimiters in #string is:
DATALENGTH(#string)-LEN(REPLACE(#string,#delimiter,''))
or
(DATALENGTH(#string)-LEN(REPLACE(#string,#delimiter,'')))/DATALENGTH(#delimiter) when dealing with delimiters longer than 1`.
WHERE DATALENGTH(#delimiter) > 0 will force the function to ignore a NULL or blank value. This is known as a Startup Predicate.
Putting a MAX around DATALENGTH(#string)-LEN(REPLACE(#string,#delimiter,'')) forces the function to rerturn a NULL value in the event you pass it a blank or NULL value.
This will return 10 for the number of spaces in my string:
SELECT f.DCount FROM dbo.CountDelimiters('one space two spaces three ', CHAR(32)) AS f;
Against a table you would use the function like this (note that I'm counting the number of times the letter "A" appears:
-- Sample Strings
DECLARE #table TABLE (SomeText VARCHAR(36));
INSERT #table VALUES('ABCABC'),('XXX'),('AAA'),(''),(NULL);
SELECT t.SomeText, f.DCount
FROM #table AS t
CROSS APPLY dbo.CountDelimiters(t.SomeText, 'A') AS f;
Which returns:
SomeText DCount
------------------------------------ -----------
ABCABC 2
XXX 0
AAA 3
0
NULL NULL
If a string has a chacacter at the end, it is considered trailing, even if there are no other characters before it. Same for logic regarding leading characters.
So ' ' can be considered an empty string ('') having a trailing space.
When I started using SQL, I also noticed the behavior that the LEN function ignores trailing spaces. And I think (but I am not sure) that is has to do with the fact that LEN should probably also behave "correctly" when used with CHAR/NCHAR values. Unlike VARCHAR/NVARCHAR, the CHAR/NCHAR values have a fixed width and will be filled with trailing spaces automatically. So when you put value 'abc' in a field/variable of type CHAR(5), the value will become 'abc ', but the LEN function will still "correctly" return 3 in that case.
I consider this just to be a strange quirk of SQL.
Remark:
The DATALENGTH function will not ignore trailing spaces in VARCHAR/NVARCHAR values. But note that DATALENGTH will return the size in bytes of the field's value. So if you use unicode data (NCHAR/NVARCHAR), the DATALENGTH function will return 6 for value N'abc', because each unicode character in SQL Server uses 2 bytes!
How to use IN condition in SQL Server when comparing Varchars with trailing spaces?
Here is a sample of the issue:
SELECT 'True'
WHERE 'Hello ' IN ('Hello', 'Goodbye', 'Hello ')
Currently this returns 'True' because SQL ignores trailing spaces when comparing VARCHAR. In this related question, this can be solved by using LIKE, however this won't work with an IN condition.
How can I ensure that the comparison takes into account the trailing spaces, specifically when using the IN condition?
Edit:
My list of acceptable values can include items with trailing spaces. Looking to compare exact values essentially (i.e 'Hello ' won't match with 'Hello ')
Assuming that your list of acceptable values do not have trailing spaces, perhaps you could use:
SELECT 'True'
WHERE 'Hello ' IN ('Hello', 'Goodbye') AND 'Hello ' NOT LIKE '% '
You could add a non-space char to the end of your search temrs:
DECLARE #Terminator char(1) = '|';
SELECT 'True'
WHERE 'Hello ' + #Terminator IN ('Hello' + #Terminator , 'Goodbye' + #Terminator)
This will force the comparison to take into account the trailing spaces while keeping everything seargable. (I assume you want to use columns either on the left or on the right side of the IN operator)
I can think of this solution on top of my head:
SELECT 'True'
WHERE reverse('Hello ') IN (reverse('Hello'), reverse('Goodbye'))
Basically this forces to compare string using reverse function.
But Zohar's solution below is most performance driven solution.
SELECT 'True'
WHERE 'Hello '+'|' IN ('Hello'+'|', 'Goodbye'+'|')
Removing leading and trailing commas
I am trying to find a way to remove trailing and leading commas in the SELECT statement. Here is some sample data: SELECT GRAIN, MATERIAL, BACKING, GRITS, REPLACE(LTRIM(RTRIM(REPLACE(PROPERTIES, ',', ' '))), ' ', ',') PROPERTIES, SPECIAL, APPLICATION, PRODUCTTYPE FROM PRODUCTFINDER I tried using trim, rtrim, and ltrim but none of them changed the strings.. Idk if I was using the wrong syntax or what, but could someone help me please? I am using SQL Server 2008.
Just another option.
This is a non-destructive approach that will eliminate any number of repeating commas and forces a final cleanup via the double pipes
For the expansion,reduction, and elimination I picked two obscure characters †‡
Example
Declare #S varchar(max) =',,,,Some,,,,,Content,,,'
Select
replace(
replace(
replace(
replace(
replace('||,' + #S + ',||', ',', '†‡'),
'‡†', ''
),
'†‡', ','
),
'||,', ''
),
',||', ''
)
Returns
Some,Content
EDIT - Removed the LTRIM()/RTRIM()
Try this:
SELECT
GRAIN, MATERIAL, BACKING, GRITS,
TRIM(',' FROM PRODUCTFINDER.PROPERTIES) AS PROPERTIES,
TRIM(',' FROM PRODUCTFINDER.SPECIAL) AS SPECIAL,
TRIM(',' FROM PRODUCTFINDER.APPLICATION) AS APPLICATION,
TRIM(',' FROM PRODUCTFINDER.PRODUCTTYPE) AS PRODUCTTYPE
FROM PRODUCTFINDER
I am not sure which columns you want to trim.
This variant of TRIM (Transact-SQL) is available since SQL-Server 2017.
If you have an earlier version of SQL-Server, do this in the Font-End (VB). This also gives you the possibility to replace multiple commas by single ones in the middle of the text.
Dim s = ",,,Abc,,,Def,Xyz,,,"
Console.WriteLine(Regex.Replace(s, ",{2,}", ",").Trim(","c))
Prints
Abc,Def,Xyz
Regex.Replace(s, ",{2,}", ",") uses the a regular expression ,{2,} to find 2 or more occurrences of commas and replaces them by one single comma. .Trim(","c) removes leading and trailing commas.
For Regex you need a
Imports System.Text.RegularExpressions
Another variant uses string split with the RemoveEmptyEntries option and then joins the parts again to form the result.
Dim s = ",,,Abc,,,Def,Xyz,,,"
Dim parts As String() = s.Split(New Char() {","c}, StringSplitOptions.RemoveEmptyEntries)
Console.WriteLine(String.Join(",", parts))
Here's one method using PATINDEX with LEFT and RIGHT.
declare #var varchar(64)= ',,,,,,,,asdf,dsf,sdfsd,asdf,,,,,,,,'
select
left(right(#var,len(#var) - patindex('%[^,]%',#var) + 1)
,len(right(#var,len(#var) - patindex('%[^,]%',#var) + 1)) - patindex('%[^,]%',reverse(right(#var,len(#var) - patindex('%[^,]%',#var) + 1))) + 1)
Just change #var to your column name.
This code strips the leading commas by searching for the first value that isn't a comma, via patindex('%[^,]%',#var) and takes everything to the RIGHT of this character. Then, we do the same thing using LEFT to remove the trailing commas.
select
Special = left(right(Special,len(Special) - patindex('%[^,]%',Special) + 1),len(right(Special,len(Special) - patindex('%[^,]%',Special) + 1)) - patindex('%[^,]%',reverse(right(Special,len(Special) - patindex('%[^,]%',Special) + 1))) + 1)
,[Application] = left(right([Application],len([Application]) - patindex('%[^,]%',[Application]) + 1),len(right([Application],len([Application]) - patindex('%[^,]%',[Application]) + 1)) - patindex('%[^,]%',reverse(right([Application],len([Application]) - patindex('%[^,]%',[Application]) + 1))) + 1)
,[ProductType] = left(right([ProductType],len([ProductType]) - patindex('%[^,]%',[ProductType]) + 1),len(right([ProductType],len([ProductType]) - patindex('%[^,]%',[ProductType]) + 1)) - patindex('%[^,]%',reverse(right([ProductType],len([ProductType]) - patindex('%[^,]%',[ProductType]) + 1))) + 1)
FROM PRODUCTFINDER
SQL Server is not ideal place for manipulating strings so trim logic should be at programming level As far as trimming particular character is required in query, refer to below thread Trimming any Leading or trailing characters
How to extract this specific substring in SQL Server?
I have a string with a specific pattern: 23;chair,red [$3] i.e., a number followed by a semicolon, then a name followed by a left square bracket. Assuming the semicolon ; always exists and the left square bracket [ always exists in the string, how do I extract the text between (and not including) the ; and the [ in a SQL Server query? Thanks.
Combine the SUBSTRING(), LEFT(), and CHARINDEX() functions.
SELECT LEFT(SUBSTRING(YOUR_FIELD,
CHARINDEX(';', YOUR_FIELD) + 1, 100),
CHARINDEX('[', YOUR_FIELD) - 1)
FROM YOUR_TABLE;
This assumes your field length will never exceed 100, but you can make it smarter to account for that if necessary by employing the LEN() function. I didn't bother since there's enough going on in there already, and I don't have an instance to test against, so I'm just eyeballing my parentheses, etc.
Assuming they always exist and are not part of your data, this will work:
declare #string varchar(8000) = '23;chair,red [$3]'
select substring(#string, charindex(';', #string) + 1, charindex(' [', #string) - charindex(';', #string) - 1)
An alternative to the answer provided by #Marc
SELECT SUBSTRING(LEFT(YOUR_FIELD, CHARINDEX('[', YOUR_FIELD) - 1), CHARINDEX(';', YOUR_FIELD) + 1, 100)
FROM YOUR_TABLE
WHERE CHARINDEX('[', YOUR_FIELD) > 0 AND
CHARINDEX(';', YOUR_FIELD) > 0;
This makes sure the delimiters exist, and solves an issue with the currently accepted answer where doing the LEFT last is working with the position of the last delimiter in the original string, rather than the revised substring.
select substring(your_field, CHARINDEX(';',your_field)+1
,CHARINDEX('[',your_field)-CHARINDEX(';',your_field)-1)
from your_table
Can't get the others to work. I believe you just want what is in between ';' and '[' in all cases regardless of how long the string in between is. After specifying the field in the substring function, the second argument is the starting location of what you will extract. That is, where the ';' is + 1 (fourth position - the c), because you don't want to include ';'. The next argument takes the location of the '[' (position 14) and subtracts the location of the spot after the ';' (fourth position - this is why I now subtract 1 in the query). This basically says substring(field,location I want substring to begin, how long I want substring to be). I've used this same function in other cases. If some of the fields don't have ';' and '[', you'll want to filter those out in the "where" clause, but that's a little different than the question. If your ';' was say... ';;;', you would use 3 instead of 1 in the example. Hope this helps!
If you need to split something into 3 pieces, such as an email address and you don't know the length of the middle part, try this (I just ran this on sqlserver 2012 so I know it works):
SELECT top 2000
emailaddr_ as email,
SUBSTRING(emailaddr_, 1,CHARINDEX('#',emailaddr_) -1) as username,
SUBSTRING(emailaddr_, CHARINDEX('#',emailaddr_)+1, (LEN(emailaddr_) - charindex('#',emailaddr_) - charindex('.',reverse(emailaddr_)) )) domain
FROM
emailTable
WHERE
charindex('#',emailaddr_)>0
AND
charindex('.',emailaddr_)>0;
GO
Hope this helps.