我试图更好地理解基于集合的逻辑并简化我正在处理的一段代码。这是我目前正在使用的示例（由于很快就会变得明显的原因，它目前不起作用）：
SELECT
userid,
rn = ROW_NUMBER() OVER (ORDER BY username)
FROM user
WHERE username like 'test%'
WHILE rn between 1 and 100
<RUN SP USING INFORMATION>
WHILE rn between 101 and 200
<RUN SP WITH DIFFERENT INFORMATION>
出于示例的目的，假设有 200 行符合SELECT语句中的条件。还假设我们不能对user表进行更改。我的问题是，不使用临时表并且（希望）不使用WHILE循环，我还能如何处理这个问题？
请注意，引用的 SP 是一个相当复杂的存储过程，需要使用该SELECT语句中的信息。我可以通过使用临时表并逐行处理这个问题，但我试图了解其他可以批量处理的方法。
几年前，我专门编写了一个基于 SQL 的实用程序来解决此类需求。本文在另一个站点的文章中有详细说明：http ://www.sqlservercentral.com/scripts/Administration/69737/ 。（如果你愿意，我也可以在这里包含它，但它相当长）
请注意以下事项：
您可能会使用此工具解决您的问题，如下所示：
EXECUTE OVER_SET '
IF {rn} between 1 and 100
<RUN SP USING INFORMATION>
IF {rn} between 101 and 200
<RUN SP WITH DIFFERENT INFORMATION>
',
@from = '
(SELECT
userid,
rn = ROW_NUMBER() OVER (ORDER BY username)
FROM user
WHERE username like ''test%'') aa '
@subs1 = '{userid}=userid',
@subs2 = '{rn}=rn',
@quote = '"' -- Allows you to use (") for quotes inside the 1st string
;
由于那是一个注册网站，我将代码发布在下面（长）：
CREATE PROC
OVER_SET (
@command AS NVARCHAR(MAX), -- Template SQL command
@from AS NVARCHAR(MAX), -- FROM..WHERE clause string
@subs1 AS NVARCHAR(MAX) = N'', -- Substitution parameters, these are
@subs2 AS NVARCHAR(MAX) = N'', -- of the form "<find>=<repl>" where:
@subs3 AS NVARCHAR(MAX) = N'', -- <find> will be searched for in @command, and
-- <repl> will replace it, if it was found
-- (typically, <repl> should be a column name
-- returned by the FROM clause)
@print AS BIT = 1, -- 0 = suppress PRINT of the SQL before executing
@catch AS VARCHAR(12) = 'continue',
-- TRY/CATCH option parameters. Choices are:
-- 'continue' on an error, print a message & continue
-- 'ignore' attempt to suppress all errors
-- 'fail' try to re-raise the error
-- 'none' no TRY/CATCH blocks
@use_db AS NVARCHAR(255) = N'', -- DB to switch to befor execution of the SQL text
@quote AS NVARCHAR(8) = N'' -- search for this character & replace with (').
)
AS
--
DECLARE @qt AS NVARCHAR(1), @cr AS NVARCHAR(1);
SELECT @qt = N'''', @cr = N'
';
DECLARE @find1 AS NVARCHAR(MAX), @prfx1 AS NVARCHAR(MAX), @sufx1 AS NVARCHAR(MAX)
DECLARE @find2 AS NVARCHAR(MAX), @prfx2 AS NVARCHAR(MAX), @sufx2 AS NVARCHAR(MAX)
DECLARE @find3 AS NVARCHAR(MAX), @prfx3 AS NVARCHAR(MAX), @sufx3 AS NVARCHAR(MAX)
DECLARE @prtst AS NVARCHAR(MAX), @prfxC AS NVARCHAR(MAX), @sufxC AS NVARCHAR(MAX)
DECLARE @newdb AS NVARCHAR(MAX), @declr AS NVARCHAR(MAX)
DECLARE @NewCmd AS NVARCHAR(MAX), @GenCmd AS NVARCHAR(MAX)
;
SELECT
@find1 = CASE WHEN @subs1 = N'' THEN N'' ELSE LEFT(@subs1,CHARINDEX(N'=',@subs1)-1) END,
@prfx1 = CASE WHEN @subs1 = N'' THEN N'' ELSE N'REPLACE(' END,
@sufx1 = CASE WHEN @subs1 = N'' THEN N'' ELSE N',@find1,'+RIGHT(@subs1,LEN(@subs1)-CHARINDEX(N'=',@subs1))+N')' END,
@find2 = CASE WHEN @subs2 = N'' THEN N'' ELSE LEFT(@subs2,CHARINDEX(N'=',@subs2)-1) END,
@prfx2 = CASE WHEN @subs2 = N'' THEN N'' ELSE N'REPLACE(' END,
@sufx2 = CASE WHEN @subs2 = N'' THEN N'' ELSE N',@find2,'+RIGHT(@subs2,LEN(@subs2)-CHARINDEX(N'=',@subs2))+N')' END,
@find3 = CASE WHEN @subs3 = N'' THEN N'' ELSE LEFT(@subs3,CHARINDEX(N'=',@subs3)-1) END,
@prfx3 = CASE WHEN @subs3 = N'' THEN N'' ELSE N'REPLACE(' END,
@sufx3 = CASE WHEN @subs3 = N'' THEN N'' ELSE N',@find3,'+RIGHT(@subs3,LEN(@subs3)-CHARINDEX(N'=',@subs3))+N')' END,
@newdb = CASE WHEN @use_db= N'' THEN N'' ELSE N'USE [' + @use_db + N'];' + @cr END,
@declr = N'DECLARE @_Num AS INT, @_Lin AS INT, @_Err AS NVARCHAR(MAX), @_Msg AS NVARCHAR(MAX);'+@cr
;
;WITH
[base] AS (SELECT cmd = @command),
[quot] AS (SELECT cmd = CASE @quote WHEN N'' THEN cmd ELSE REPLACE(cmd, @quote, @qt) END FROM [base]),
[dble] AS (SELECT cmd = N'N'+@qt+REPLACE(cmd, @qt, @qt+@qt)+@qt FROM [quot]),
[prnt] AS (SELECT cmd = CASE @print WHEN 1 THEN N' PRINT '+cmd+';'+@cr ELSE N'' END
+ N' EXEC('+cmd+N');' FROM [dble]),
[ctch] AS (SELECT cmd =
CASE @catch WHEN N'none' THEN cmd
ELSE N'BEGIN TRY'+@cr+cmd+@cr+N'END TRY'+@cr+N'BEGIN CATCH'+@cr
+ N' SELECT @_Num=ERROR_NUMBER(), @_Lin=ERROR_LINE(), @_Err=ERROR_MESSAGE()'+@cr
+ CASE @catch
WHEN N'continue' THEN
N' SELECT @_msg=''Continuing after Error(''+CAST(@_Num AS NVARCHAR)+'') at Line ''+CAST(@_Lin AS NVARCHAR)+'''
+@cr+' ''+@_Err;'+@cr
+N' PRINT @_msg; '+@cr
+N' PRINT '' ''; '+@cr
WHEN N'ignore' THEN N' -- ignore = do nothing'+@cr
WHEN N'fail' THEN
N' SELECT @_msg=''Failing after Error(''+CAST(@_Num AS NVARCHAR)+'') at Line ''+CAST(@_Lin AS NVARCHAR)+'''
+@cr+' ''+@_Err;'+@cr
+N' RAISERROR(@_Num, 16, 1);'+@cr
+N' PRINT '' ''; '+@cr
ELSE N' --BAD else branch, shouldnt get here' END
+ N'END CATCH;' END FROM [prnt])
SELECT
@NewCmd = @prfx1+@prfx2+@prfx3+ N'@command' +@sufx1+@sufx2+@sufx3,
@command = cmd + @cr
FROM [ctch]
;
SELECT @GenCmd = '
DECLARE @sql AS NVARCHAR(MAX); SET @sql = '''+@newdb+ +@declr+ '''
;WITH
[-@from] AS ( SELECT * FROM ' +@from+ ' )
, [-@subs] AS ( SELECT [-NewCmd] = ' +@NewCmd+ ' FROM [-@from] )
, [-@print] AS ( SELECT [-NewCmd] = [-NewCmd] FROM [-@subs] )
SELECT
@sql = @sql + ''
'' + [-NewCmd]
FROM [-@subs]
;
EXEC sp_executesql @sql;
'
;
EXEC sp_executesql @GenCmd
, N'@command NVARCHAR(MAX), @from NVARCHAR(MAX), @find1 NVARCHAR(MAX), @find2 NVARCHAR(MAX), @find3 NVARCHAR(MAX)'
, @command, @from, @find1, @find2, @find3
;
以下是包含一些示例的帖子评论：
Example Usages
1) INSERT..EXECute:
Demonstrates capturing the SELECT output from an EXECUTE OVER_SET that
searches every database in the SQL Server Instance for routines with
the work "cursor" in them.
--
CREATE TABLE #temp (DB sysname, [Schema] sysname, Routine sysname);
INSERT INTO #temp
EXECUTE OVER_SET '
SELECT ROUTINE_CATALOG, ROUTINE_SCHEMA, ROUTINE_NAME
FROM [{db}].INFORMATION_SCHEMA.ROUTINES
WHERE ROUTINE_DEFINITION like "%cursor%"',
@from = 'sys.sysdatabases WHERE dbid > 4',
@subs1 = '{db}=name',
@quote = '"'
;
SELECT * from #temp;
DROP table #temp;
--
The @from argument returns the list of non-system databases in the server,
and the @susbs1 argument "{db}=name" tells it to replace every instance
of "{db}" in the command strings with the value of the [name] column (from
sys.sysdatabases). Note also the @quote argument's value (") allows us to
use a single quotation mark in the quoted command text instead of having
to use double apostrophes (ie, ' "%cursor%" ', instead of ' ''%cursor%'' ').
--======
2) Nested Example:
Demonstrates, nesting OVER_SET execution to operate against the combination
of to different sets, the second dependent on the first. Specifically,
it searches every non-system database for every user that is a windows
user or group, and then attempts to map them back to a server Login of
the same name.
--
EXECUTE OVER_SET '
EXECUTE OVER_SET "
ALTER USER [{name}] WITH LOGIN = [{name}];
PRINT `USER {name} has been mapped to its Login.`;",
@from = "sys.database_principals
WHERE ( type_desc = ""WINDOWS_GROUP"" OR type_desc = ""WINDOWS_USER"" )
AND name NOT like ""%dbo%"" AND name NOT LIKE ""%#%"" ",
@use_db = "{db}",
@subs1 = "{name}=name",
@catch = "continue",
@print = 1,
@quote = "`";
',
@from = 'sys.sysdatabases
WHERE dbid > 4',
@subs1 = '{db}=name',
@catch = 'continue',
@print = 0,
@quote = '"';
--
The outer OVER_SET uses the @from argument to return the list of all databases
which the @subs1 argument "{db}=name", uses to modify the inner OVER_SET
commands @use_db argument, cuasing the inner execution to USE [{db}} to each
database in turn. The inner execution's @from argument returns the list
of database users that are WINDOWS_* user or group, and the @subs1 ({name}=name)
cause the "{name}" token to be replaced with the value of the [name] column
from the database_principals table.
Note that two different @quote characters are used ( ("), then (`) ), removing
the need for double or even quadruple apostrophes in the inner command text.
(also note, that the @from argument text does not benefit from this, and can
only use the outer command quote (") becuase it is part of the outer command
text argument.
您不能将存储过程作为另一个查询的一部分来调用，因此如果不重写存储过程，就不可能按照基于集合的操作来执行您所要求的操作。
是否可以使用 UDF 代替 SP？在这种情况下，您可以一次性将 UDF 与 SELECT 语句中的参数包括在内。显然 UDF 有局限性，但我想这取决于你的 SP 的复杂性。