Related
I am trying to create a routine that can accept an SQL query as a string and the [table].[primaryKey] of the primary record in the returned dataset, then wrap that original query to implement pagination (return records 40-49 when requesting page 4 and 10 records per page).
The dataset returned by the original queries will frequently contain multiple instances of the primary record, one for each occurrence of supporting records. For the example provided, if a customer has three phone numbers on record the results for that customer in the original query would look like:
{5; John Smith; 205 W. Fort St; 17; Home; 123-123-4587}
{5; John Smith; 205 W. Fort St; 18; Work; 123-123-8547}
{5; John Smith; 205 W. Fort St; 19; Mobile; 123-123-1147}
I'm almost there, I think, with the following query:
DECLARE #PageNumber int = 4;
DECLARE #RecordsPerPage int = 10;
WITH OriginalQuery AS (
SELECT [Customer].[Id],
[Customer].[Name],
[Customer].[Address],
[Phone].[Id],
[Phone].[Type],
[Phone].[Number]
FROM [Customer] INNER JOIN [Phone] ON [Customer].[Id] = [Phone].[CustomerId]
)
SELECT [WrappedQuery].[RowNumber], [OriginalQuery].* FROM (
SELECT ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) [RowNumber], *
FROM (
SELECT DISTINCT [OriginalQuery].[{Customer.Id}] [PrimaryKey]
FROM [OriginalQuery]
) [RuwNumberQuery]
) [WrappedQuery]
INNER JOIN [OriginalQuery] ON [WrappedQuery].[PrimaryKey] = [OriginalQuery].[{Customer.Id}]
WHERE [WrappedQuery].[RowNumber] >= #PageNumber
AND [WrappedQuery].[RowNumber] < #PageNumber + #RecordsPerPage
This solution performs a SELECT DISTINCT on the primary key for the Primary (Customer) record and uses the SQL routine Row_Number() then joins the result with the results of the original query such that each unique primary (customer) record is numbered 1 - {end of file}, and I can pull only the RowNumber counts that I want.
But because OriginalQuery may have multiple fields named Id (from different tables), I can't figure out how to properly access [Customer].[Id] in my SELECT DISTINCT clause of [RowNumberQuery] or in the INNER JOIN.
Is there a better way to implement pagination at the SQL level, or a more direct method of accessing the field I need from within the subquery based on the table to which it belongs?
EDIT:
I've caused confusion in the pagination I am looking for. I am using Dapper in C# to compile the resulting dataset into individual complex objects, so the goal in the example would be to retrieve customers 31-40 in the list regardless of how many individual records exist for each customer. If Customer 31 had five phone records, Customer 32 had three phone records, Customer 33 had 1 phone record, and the remaining seven customers had two phone records each, I would expect the resulting dataset to contain 23 records total, but only 10 distinct customers.
SOLUTION
Thank you for all of the assistance, and I apologize for those areas I should have clarified sooner. I am creating a toolset that will allow C# Data Access Libraries to implement a set of standard parameters. If I have an option to implement the pagination in an internal function that can accept the SQL statement, I can defer to the toolset and not have to remember (or count on others to remember) to add the appropriate text each time. I'll set it up to return the finished objects, but if I were going to just modify the original query string it would look like:
public static string AddPagination(string sql, string primaryKey, Parameter requestParameters)
{
return $"WITH OriginalQuery AS ({sql.Replace("SELECT ", $"SELECT DENSE_RANK() OVER (ORDER BY {primaryKey}) AS PrimaryRecordCount, ",StringComparison.OrdinalIgnoreCase)}) " +
$"SELECT TOP ({requestParameters.MaxRecords}) * " +
$"FROM OriginalQuery " +
$"WHERE PrimaryRecordCount >= 1 + (({requestParameters.PageNumber - 1}) * {requestParameters.RecordsPerPage})" +
$" AND PrimaryRecordCount <= {requestParameters.Page} * {requestParameters.Limit}";
}
Just give your columns a different alias in your original query, e.g. [Customer].[Id] AS CustomerId, [Phone].[Id] AS PhoneId..., then you can reference OriginalQuery.CustomerId, or OriginalQuery.PhoneId
e.g.
DECLARE #PageNumber int = 4;
DECLARE #RecordsPerPage int = 10;
WITH OriginalQuery AS (
SELECT [Customer].[Id] AS CustomerId,
[Customer].[Name],
[Customer].[Address],
[Phone].[Id] AS PhoneId,
[Phone].[Type],
[Phone].[Number]
FROM [Customer] INNER JOIN [Phone] ON [Customer].[Id] = [Phone].[CustomerId]
)
SELECT [WrappedQuery].[RowNumber], [OriginalQuery].* FROM (
SELECT ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) [RowNumber], *
FROM (
SELECT DISTINCT [OriginalQuery].[{Customer.Id}] [PrimaryKey]
FROM [OriginalQuery]
) [RuwNumberQuery]
) [WrappedQuery]
INNER JOIN [OriginalQuery] ON [WrappedQuery].[PrimaryKey] = [OriginalQuery].[CustomerId]
WHERE [WrappedQuery].[RowNumber] >= #PageNumber
AND [WrappedQuery].[RowNumber] < #PageNumber + #RecordsPerPage
It's worth noting that your paging logic is wrong too. Currently you are adding page number to the number of pages so you are searching for:
Page 1: Customers 1 - 10
Page 2: Customers 2 - 11
Page 3: Customers 3 - 12
Your logic should be:
WHERE [WrappedQuery].[RowNumber] >= 1 + ((#PageNumber - 1) * #RecordsPerPage)
AND [WrappedQuery].[RowNumber] <= (#PageNumber * #RecordsPerPage)
Page 1: Customers 1 - 10
Page 2: Customers 11 - 20
Page 3: Customers 21 - 30
With that being said, you could just use DENSE_RANK() Rather than ROW_NUMBER which would simplify everything. I think this would give you the same result:
DECLARE #PageNumber int = 4;
DECLARE #RecordsPerPage int = 10;
WITH OriginalQuery AS (
SELECT c.Id AS CustomerId,
c.Name,
c.Address,
p.Id AS PhoneId,
p.Type,
p.Number,
DENSE_RANK() OVER(ORDER BY c.Id) AS RowNumber
FROM Customer AS c INNER JOIN Phone AS p ON c.Id = p.CustomerId
)
SELECT oq.CustomerId, oq.Name, oq.Address, oq.PhoneId, oq.Type, oq.Number
FROM OriginalQuery AS oq
WHERE oq.RowNumber >= 1 +((#PageNumber - 1) * #RecordsPerPage)
AND oq.RowNumber <= (#PageNumber * #RecordsPerPage);
I've added table aliases to try and make the code a bit cleaner, and also removed all the unnecessary square brackets. This is not necessary, but I personally find them quite hard on the eye, and only use them to escape key words.
Another difference is that in adding ORDER BY c.CustomerId you ensure consistent results for your paging. Using ORDER BY (SELECT NULL) implies that you don't care about the order, but you should if you using it for paging.
There are many concerns with what you are trying to do and you might be better off explaining why you are trying to make this process.
SQL query as a string
You are receiving a SQL query as a string, how are you parsing that string into the OriginalQuery CTE? This has both concerns about sql injection and concerns about global temp tables if you are using those.
Secondly, your example isn't doing pagination as it is commonly understood. If someone were to request page 1, 10 records per page, the calling application would expect to receive the first 10 records of the result set but your example will returns all records for the first 10 customers. Meaning the result could be 40+ if they each had 4 phone numbers as in your example data.
You should take a look at OFFSET and FETCH NEXT, as well as why this requirement to parse an arbitrary SQL string. There is probably a better way to do that.
Here is a rough example using OFFSET and FETCH NEXT from a static query, and returning only #RecordsPerPage number of records.
DECLARE #PageNumber int = 1;
DECLARE #RecordsPerPage int = 10;
SELECT [Customer].[Id],
[Customer].[Name],
[Customer].[Address],
[Phone].[Id],
[Phone].[Type],
[Phone].[Number]
FROM [Customer] INNER JOIN [Phone] ON [Customer].[Id] = [Phone].[CustomerId]
ORDER BY [Customer].[Id]
OFFSET (#PageNumber-1)*#RecordsPerPage rows
FETCH NEXT #RecordsPerPage ROWS ONLY
If you wanted to return all records for the the RecordsPerPage number of entries which have a corresponding phone number, then it would be something like...
DECLARE #PageNumber int = 1;
DECLARE #RecordsPerPage int = 10;
SELECT [Customer].[Id],
[Customer].[Name],
[Customer].[Address],
[Phone].[Id],
[Phone].[Type],
[Phone].[Number]
FROM [Customer] INNER JOIN [Phone] ON [Customer].[Id] = [Phone].[CustomerId]
WHERE Customer.ID IN (
SELECT DISTINCT Customer.ID FROM Customer INNER JOIN [Phone] ON [Customer].[Id] = [Phone].[CustomerId]
ORDER BY [Customer].[Id]
OFFSET (#PageNumber-1)*#RecordsPerPage rows
FETCH NEXT #RecordsPerPage ROWS ONLY
)
This does leave a question, what is the point of this query when the calling application can just use their own OFFSET and FETCH NEXT? They already have the SQL to generate the initial dataset, all they need to do is add OFFSET / FETCH NEXT to the end of it and they have their own pagination without trying to wrap it in a procedure of some sort.
To create a comparison, would you create a stored procedure that accepts a SQL string and then filters specific fields by specific values? Or would the people calling that stored procedure just add a Where clause to their own queries instead?
You can use alias name for the cuplicated column.
For example:
WITH OriginalQuery AS (
SELECT [Customer].[Id] as CustomerID,
[Customer].[Name],
[Customer].[Address],
[Phone].[Id] as PhoneID,
[Phone].[Type],
[Phone].[Number]
FROM [Customer] INNER JOIN [Phone] ON [Customer].[Id] = [Phone].[CustomerId]
)
now you can use the 2 ids whit the alias name for the next query.
We handle a lot of sensitive data and I would like to mask passenger names using only the first and last letter of each name part and join these by three asterisks (***),
For example: the name 'John Doe' will become 'J***n D***e'
For a name that consists of two parts this is doable by finding the space using the expression:
LEFT(CardHolderNameFromPurchase, 1) +
'***' +
CASE WHEN CHARINDEX(' ', PassengerName) = 0
THEN RIGHT(PassengerName, 1)
ELSE SUBSTRING(PassengerName, CHARINDEX(' ', PassengerName) -1, 1) +
' ' +
SUBSTRING(PassengerName, CHARINDEX(' ', PassengerName) +1, 1) +
'***' +
RIGHT(PassengerName, 1)
END
However, the passenger name can have more than two parts, there is no real limit to it. How should can I find the indices of all spaces within an expression? Or should I maybe tackle this problem in a different way?
Any help or pointer is much appreciated!
This solution does what you want it to, but is really the wrong approach to use when trying to hide personally identifiable data, as per Gordon's explanation in his answer.
SQL:
declare #t table(n nvarchar(20));
insert into #t values('John Doe')
,('JohnDoe')
,('John Doe Two')
,('John Doe Two Three')
,('John O''Neill');
select n
,stuff((select ' ' + left(s.item,1) + '***' + right(s.item,1)
from dbo.fn_StringSplit4k(t.n,' ',null) as s
for xml path('')
),1,1,''
) as mask
from #t as t;
Output:
+--------------------+-------------------------+
| n | mask |
+--------------------+-------------------------+
| John Doe | J***n D***e |
| JohnDoe | J***e |
| John Doe Two | J***n D***e T***o |
| John Doe Two Three | J***n D***e T***o T***e |
| John O'Neill | J***n O***l |
+--------------------+-------------------------+
String splitting function based on Jeff Moden's Tally Table approach:
create function [dbo].[fn_StringSplit4k]
(
#str nvarchar(4000) = ' ' -- String to split.
,#delimiter as nvarchar(1) = ',' -- Delimiting value to split on.
,#num as int = null -- Which value to return, null returns all.
)
returns table
as
return
-- Start tally table with 10 rows.
with n(n) as (select 1 union all select 1 union all select 1 union all select 1 union all select 1 union all select 1 union all select 1 union all select 1 union all select 1 union all select 1)
-- Select the same number of rows as characters in #str as incremental row numbers.
-- Cross joins increase exponentially to a max possible 10,000 rows to cover largest #str length.
,t(t) as (select top (select len(isnull(#str,'')) a) row_number() over (order by (select null)) from n n1,n n2,n n3,n n4)
-- Return the position of every value that follows the specified delimiter.
,s(s) as (select 1 union all select t+1 from t where substring(isnull(#str,''),t,1) = #delimiter)
-- Return the start and length of every value, to use in the SUBSTRING function.
-- ISNULL/NULLIF combo handles the last value where there is no delimiter at the end of the string.
,l(s,l) as (select s,isnull(nullif(charindex(#delimiter,isnull(#str,''),s),0)-s,4000) from s)
select rn
,item
from(select row_number() over(order by s) as rn
,substring(#str,s,l) as item
from l
) a
where rn = #num
or #num is null;
GO
If you consider PassengerName as sensitive information, then you should not be storing it in clear text in generally accessible tables. Period.
There are several different options.
One is to have reference tables for sensitive information. Any table that references this would have an id rather than the name. Viola. No sensitive information is available without access to the reference table, and that would be severely restricted.
A second method is a reversible compression algorithm. This would allow the the value to be gibberish, but with the right knowledge, it could be transformed back into a meaningful value. Typical methods for this are the public key encryption algorithms devised by Rivest, Shamir, and Adelman (RSA encoding).
If you want to do first and last letters of names, I would be really careful about Asian names. Many of them consist of two or three letters, when written in Latin script. That isn't much hiding. SQL Server does not have simple mechanisms to do this. You can write a user-defined function with a loop to manager the process. However, I view this as the least secure and least desirable approach.
This uses Jeff Moden's DelimitedSplit8K, as well as the new functionality in SQL Server 2017 STRING_AGG. As I don't know what version you're using, I've just gone "whole hog" and assumed you're using the latest version.
Jeff's function is invaluable here, as it returns the ordinal position, something which Microsoft have foolishly omitted from their own function, STRING_SPLIT (and didn't add in 2017 either). Ordinal position is key here, so we can't make use of the built in function.
WITH VTE AS(
SELECT *
FROM (VALUES ('John Doe'),('Jane Bloggs'),('Edgar Allan Poe'),('Mr George W. Bush'),('Homer J Simpson')) V(FullName)),
Masking AS (
SELECT *,
ISNULL(STUFF(Item, 2, LEN(item) -2,'***'), Item) AS MaskedPart
FROM VTE V
CROSS APPLY dbo.delimitedSplit8K(V.Fullname, ' '))
SELECT STRING_AGG(MaskedPart,' ') AS MaskedFullName
FROM Masking
GROUP BY Fullname;
Edit: Nevermind, OP has commented they are using 2008, so STRING_AGG is out of the question. #iamdave, however, has posted an answer which is very similar to my own, just do it the "old fashioned XML way".
Depending on your version of SQL Server, you may be able to use the built-in string split to rows on spaces in the name, do your string formatting, and then roll back up to name level using an XML path.
create table dataset (id int identity(1,1), name varchar(50));
insert into dataset (name) values
('John Smith'),
('Edgar Allen Poe'),
('One Two Three Four');
with split as (
select id, cs.Value as Name
from dataset
cross apply STRING_SPLIT (name, ' ') cs
),
formatted as (
select
id,
name,
left(name, 1) + '***' + right(name, 1) as out
from split
)
SELECT
id,
(SELECT ' ' + out
FROM formatted b
WHERE a.id = b.id
FOR XML PATH('')) [out_name]
FROM formatted a
GROUP BY id
Result:
id out_name
1 J***n S***h
2 E***r A***n P***e
3 O***e T***o T***e F***r
You can do that using this function.
create function [dbo].[fnMaskName] (#var_name varchar(100))
RETURNS varchar(100)
WITH EXECUTE AS CALLER
AS
BEGIN
declare #var_part varchar(100)
declare #var_return varchar(100)
declare #n_position smallint
set #var_return = ''
set #n_position = 1
WHILE #n_position<>0
BEGIN
SET #n_position = CHARINDEX(' ', #var_name)
IF #n_position = 0
SET #n_position = LEN(#var_name)
SET #var_part = SUBSTRING(#var_name, 1, #n_position)
SET #var_name = SUBSTRING(#var_name, #n_position+1, LEN(#var_name))
if #var_part<>''
SET #var_return = #var_return + stuff(#var_part, 2, len(#var_part)-2, replicate('*',len(#var_part)-2)) + ' '
END
RETURN(#var_return)
END
I am currently working on a table with approx. 7.5mio rows and 16 columns. One of the rows is an internal identifier (let's call it ID) we use at my university. Another column contains a string.
So, ID is NOT the unique index for a row, so it is possible that one identifier appears more than once in the table - the only difference between the two rows being the string.
I need to find all rows with ID and just keep the one with the longest string and deleting every other row from the original table. Unfortunately I am more of a SQL Novice, and I am really stuck at this point. So if anyone could help, this would be really nice.
Take a look at this sample:
SELECT * INTO #sample FROM (VALUES
(1, 'A'),
(1,'Long A'),
(2,'B'),
(2,'Long B'),
(2,'BB')
) T(ID,Txt)
DELETE S FROM (
SELECT *, ROW_NUMBER() OVER (PARTITION BY ID ORDER BY LEN(Txt) DESC) RN
FROM #sample) S
WHERE RN!=1
SELECT * FROM #sample
Results:
ID Txt
-- ------
1 Long A
2 Long B
It might be possible just in SQL, but the way I know how to do it would be a two-pass approach using application code - I assume you have an application you are writing.
The first pass would be something like:
SELECT theid, count(*) AS num, MAX(LEN(thestring)) AS keepme FROM thetable WHERE num > 1 GROUP BY theid
Then you'd loop through the results in whatever language you're using and delete anything with that ID except the one matching the string returned. The language I know is PHP, so I'll use it for my example, but the method would be the same in any language (for brevity, I'm skipping error checking, prepared statements, and such, and not testing - please use carefully):
$sql = 'SELECT theid, count(*) AS num, MAX(LEN(thestring)) AS keepme FROM thetable WHERE num > 1 GROUP BY theid';
$result = sqlsrv_query($resource, $sql);
while ($row = sqlsrv_fetch_object($result)) {
$sql = 'DELETE FROM thetable WHERE theid = '.$row->theid.' AND NOT thestring = '.$row->keepme;
$result = sqlsrv_query($resource, $sql);
}
You didn't say what you would want to do if two strings are the same length, so this solution does not deal with that at all - I'm assuming that each ID will only have one longest string.
My question is not exactly but similar to this question
How to SELECT parts from a comma-separated field with a LIKE statement
but i have not seen any answer there. So I am posting my question again.
i have the following table
╔════════════╦═════════════╗
║ VacancyId ║ Media ║
╠════════════╬═════════════╣
║ 1 ║ 32,26,30 ║
║ 2 ║ 31, 25,20 ║
║ 3 ║ 21,32,23 ║
╚════════════╩═════════════╝
I want to select data who has media id=30 or media=21 or media= 40
So in this case the output will return the 1st and the third row.
How can I do that ?
I have tried media like '30' but that does not return any value. Plus i just dont need to search for one string in that field .
My database is SQL Server
Thank you
It's never good to use the comma separated values to store in database if it is feasible try to make separate tables to store them as most probably this is 1:n relationship.
If this is not feasible then there are following possible ways you can do this,
If your number of values to match are going to stay same, then you might want to do the series of Like statement along with OR/AND depending on your requirement.
Ex.-
WHERE
Media LIKE '%21%'
OR Media LIKE '%30%'
OR Media LIKE '%40%'
However above query will likely to catch all the values which contains 21 so even if columns with values like 1210,210 will also be returned. To overcome this you can do following trick which is hamper the performance as it uses functions in where clause and that goes against making Seargable queries.
But here it goes,
--Declare valueSearch variable first to value to match for you can do this for multiple values using multiple variables.
Declare #valueSearch = '21'
-- Then do the matching in where clause
WHERE
(',' + RTRIM(Media) + ',') LIKE '%,' + #valueSearch + ',%'
If the number of values to match are going to change then you might want to look into FullText Index and you should thinking about the same.
And if you decide to go with this after Fulltext Index you can do as below to get what you want,
Ex.-
WHERE
CONTAINS(Media, '"21" OR "30" OR "40"')
The best possible way i can suggest is first you have do comma separated value to table using This link and you will end up with table looks like below.
SELECT * FROM Table
WHERE Media in('30','28')
It will surely works.
You can use this, but the performance is inevitably poor. You should, as others have said, normalise this structure.
WHERE
',' + media + ',' LIKE '%,21,%'
OR ',' + media + ',' LIKE '%,30,%'
Etc, etc...
If you are certain that any Media value containing the string 30 will be one you wish to return, you just need to include wildcards in your LIKE statement:
SELECT *
FROM Table
WHERE Media LIKE '%30%'
Bear in mind though that this would also return a record with a Media value of 298,300,302 for example, so if this is problematic for you, you'll need to consider a more sophisticated method, like:
SELECT *
FROM Table
WHERE Media LIKE '%,30,%'
OR Media LIKE '30,%'
OR Media LIKE '%,30'
OR Media = '30'
If there might be spaces in the strings (as per in your question), you'll also want to strip these out:
SELECT *
FROM Table
WHERE REPLACE(Media,' ','') LIKE '%,30,%'
OR REPLACE(Media,' ','') LIKE '30,%'
OR REPLACE(Media,' ','') LIKE '%,30'
OR REPLACE(Media,' ','') = '30'
Edit: I actually prefer Coder of Code's solution to this:
SELECT *
FROM Table
WHERE ',' + LTRIM(RTRIM(REPLACE(Media,' ',''))) + ',' LIKE '%,30,%'
You mention that would wish to search for multiple strings in this field, which is also possible:
SELECT *
FROM Table
WHERE Media LIKE '%30%'
OR Media LIKE '%28%'
SELECT *
FROM Table
WHERE Media LIKE '%30%'
AND Media LIKE '%28%'
I agree not a good idea comma seperated values stored like that. Bu if you have to;
I think using inline function is will give better performance;
Select VacancyId, Media from (
Select 1 as VacancyId, '32,26,30' as Media
union all
Select 2, '31,25,20'
union all
Select 3, '21,32,23'
) asa
CROSS APPLY dbo.udf_StrToTable(Media, ',') tbl
where CAST(tbl.Result as int) in (30,21,40)
Group by VacancyId, Media
Output is;
VacancyId Media
----------- ---------
1 32,26,30
3 21,32,23
and our inline function script is;
if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[udf_StrToTable]') and xtype in (N'FN', N'IF', N'TF'))
drop function [dbo].udf_StrToTable
GO
CREATE FUNCTION udf_StrToTable (#List NVARCHAR(MAX), #Delimiter NVARCHAR(1))
RETURNS TABLE
With Encryption
AS
RETURN
( WITH Split(stpos,endpos)
AS(
SELECT 0 AS stpos, CHARINDEX(#Delimiter,#List) AS endpos
UNION ALL
SELECT CAST(endpos+1 as int), CHARINDEX(#Delimiter,#List,endpos+1)
FROM Split
WHERE endpos > 0
)
SELECT ROW_NUMBER() OVER (ORDER BY (SELECT 1)) as inx,
SUBSTRING(#List,stpos,COALESCE(NULLIF(endpos,0),LEN(#List)+1)-stpos) Result
FROM Split
)
GO
This solution uses a RECURSIVE CTE to identify the position of each comma within the string then uses SUBSTRING to return all strings between the commas.
I've left some unnecessary code in place to help you get you head round what it's doing. You can strip it down to provide exactly what you need.
DROP TABLE #TMP
CREATE TABLE #TMP(ID INT, Vals CHAR(100))
INSERT INTO #TMP(ID,VALS)
VALUES
(1,'32,26,30')
,(2,'31, 25,20')
,(3,'21,32,23')
;WITH cte
AS
(
SELECT
ID
,VALS
,0 POS
,CHARINDEX(',',VALS,0) REM
FROM
#TMP
UNION ALL
SELECT ID,VALS,REM,CHARINDEX(',',VALS,REM+1)
FROM
cte c
WHERE CHARINDEX(',',VALS,REM+1) > 0
UNION ALL
SELECT ID,VALS,REM,LEN(VALS)
FROM
cte c
WHERE POS+1 < LEN(VALS) AND CHARINDEX(',',VALS,REM+1) = 0
)
,cte_Clean
AS
(
SELECT ID,CAST(REPLACE(LTRIM(RTRIM(SUBSTRING(VALS,POS+1,REM-POS))),',','') AS INT) AS VAL FROM cte
WHERE POS <> REM
)
SELECT
ID
FROM
cte_Clean
WHERE
VAL = 32
ORDER BY ID
I've got this Oracle code structure I'm trying to convert to SQL Server 2008 (Note: I have used generic names, enclosed column names and table names within square brackets '[]', and done some formatting to make the code more readable):
SELECT [col#1], [col#2], [col#3], ..., [col#n], [LEVEL]
FROM (SELECT [col#1], [col#2], [col#3], ..., [col#n]
FROM [TABLE_1]
WHERE ... )
CONNECT BY PRIOR [col#1] = [col#2]
START WITH [col#2] IS NULL
ORDER SIBLINGS BY [col#3]
What is the SQL Server equivalent template of the above code?
Specifically, I'm struggling with the LEVEL, and 'ORDER SIBLINGS BY' Oracle constructs.
Note:
The above "code" is the final output from a set of Oracle procedures. Basically, the 'WHERE' clause is built up dynamically and changes depending on various parameters passed. The code block starting with 'CONNECT BY PRIOR' is hard-coded.
For Reference:
The Simulation of CONNECT BY PRIOR of ORACLE in SQL SERVER article comes close, but it does not explain how to handle the 'LEVEL' and the 'ORDER SIBLINGS' constructs. ... And my mind is getting in a twist!
SELECT name
FROM emp
START WITH name = 'Joan'
CONNECT BY PRIOR empid = mgrid
equates to:
WITH n(empid, name) AS
(SELECT empid, name
FROM emp
WHERE name = 'Joan'
UNION ALL
SELECT nplus1.empid, nplus1.name
FROM emp as nplus1, n
WHERE n.empid = nplus1.mgrid)
SELECT name FROM n
If I have an initial template to work from, it will go a long way to helping me construct SQL Server stored procs to build up a correct T-SQL statement.
Assistance will be much appreciated.
Simulating the LEVEL column
The level column can easily be simulated by incrementing a counter in the recursive part:
WITH tree (empid, name, level) AS (
SELECT empid, name, 1 as level
FROM emp
WHERE name = 'Joan'
UNION ALL
SELECT child.empid, child.name, parent.level + 1
FROM emp as child
JOIN tree parent on parent.empid = child.mgrid
)
SELECT name
FROM tree;
Simulating order siblings by
Simulating the order siblings by is a bit more complicated. Assuming we have a column sort_order that defines the order of elements per parent (not the overall sort order - because then order siblings wouldn't be necessary) then we can create a column which gives us an overall sort order:
WITH tree (empid, name, level, sort_path) AS (
SELECT empid, name, 1 as level,
cast('/' + right('000000' + CONVERT(varchar, sort_order), 6) as varchar(max))
FROM emp
WHERE name = 'Joan'
UNION ALL
SELECT child.empid, child.name, parent.level + 1,
parent.sort_path + '/' + right('000000' + CONVERT(varchar, child.sort_order), 6)
FROM emp as child
JOIN tree parent on parent.empid = child.mgrid
)
SELECT *
FROM tree
order by sort_path;
The expression for the sort_path looks so complicated because SQL Server (at least the version you are using) does not have a simple function to format a number with leading zeros. In Postgres I would use an integer array so that the conversion to varchar isn't necessary - but that doesn't work in SQL Server either.
The option given by the user "a_horse_with_no_name" worked for me. I changed the code and applied it to a menu generator query and it worked the first time. Here is the code:
WITH tree(option_id,
option_description,
option_url,
option_icon,
option_level,
sort_path)
AS (
SELECT ppo.option_id,
ppo.option_description,
ppo.option_url,
ppo.option_icon,
1 AS option_level,
CAST('/' + RIGHT('00' + CONVERT(VARCHAR, ppo.option_index), 6) AS VARCHAR(MAX))
FROM security.options_table_name ppo
WHERE ppo.option_parent_id IS NULL
UNION ALL
SELECT co.option_id,
co.option_description,
co.option_url,
co.option_icon,
po.option_level + 1,
po.sort_path + '/' + RIGHT('00' + CONVERT(VARCHAR, co.option_index), 6)
FROM security.options_table_name co,
tree AS po
WHERE po.option_id = co.option_parent_id)
SELECT *
FROM tree
ORDER BY sort_path;
to get dates for last 10 days:
SELECT DISTINCT RecordDate = DATEADD(DAY,-number,CAST(GETDATE() AS DATE))
FROM master..[spt_values]
WHERE number BETWEEN 1 AND 10