¶¯Ì¬sqlÓï¾ä»ù±¾Óï·¨

SQL code
¶¯Ì¬sqlÓï¾ä»ù±¾Óï·¨
1 :ÆÕͨSQLÓï¾ä¿ÉÒÔÓÃExecÖ´ÐÐ
eg: Select * from tableName
Exec('select * from tableName')
Exec sp_executesql N'select * from tableName' -- Çë×¢Òâ×Ö·û´®Ç°Ò»¶¨Òª¼ÓN
2:×Ö¶ÎÃû£¬±íÃû£¬Êý¾Ý¿âÃûÖ®Àà×÷Ϊ±äÁ¿Ê±£¬±ØÐëÓö¯Ì¬SQL
eg:
declare @fname varchar(20)
set @fname = 'FiledName'
Select @fname from tableName -- ´íÎó,²»»áÌáʾ´íÎ󣬵«½á¹ûΪ¹Ì¶¨ÖµFiledName,²¢·ÇËùÒª¡£
Exec('select ' + @fname + ' from tableName') -- Çë×¢Òâ ¼ÓºÅÇ°ºóµÄ µ¥ÒýºÅµÄ±ßÉϼӿոñ
µ±È»½«×Ö·û´®¸Ä³É±äÁ¿µÄÐÎʽҲ¿É
declare @fname varchar(20)
set @fname = 'FiledName' --ÉèÖÃ×Ö¶ÎÃû
declare @s varchar(1000)
set @s = 'select ' + @fname + ' from tableName'
Exec(@s) -- ³É¹¦
exec sp_executesql @s -- ´Ë¾ä»á±¨´í
declare @s Nvarchar(1000) -- ×¢Òâ´Ë´¦¸ÄΪnvarchar(1000)
set @s = 'select ' + @fname + ' from tableName'
Exec(@s) -- ³É¹¦
exec sp_executesql @s -- ´Ë¾äÕýÈ·
3. Êä³ö²ÎÊý
declare @num int,
@sqls nvarchar(4000)
set @sqls='select count(*) from tableName'
exec(@sqls)
--ÈçºÎ½«execÖ´Ðнá¹û·ÅÈë±äÁ¿ÖУ¿
declare @num int,
@sqls nvarchar(4000)
set @sqls='select @a=count(*) from tableName '
exec sp_executesql @sqls,N'@a int output',@num output
select @num