笔记30 like语句的sql并接

笔记30 like语句的sql并接

 1 --like语句的sql并接
 2 declare @CdtSQL varchar(max)
 3 SET @CdtSQL = @CdtSQL + 'and CT_OuterCard.VC_OC_Company like ''%'
 4 print @CdtSQL -- 因为@CdtSQL没给初始值会是null,所以null + 'and CT_OuterCard.VC_OC_Company like ''%',得到的结果还是null
 5 SET @CdtSQL = '' -- 设定初始值为空字符串后,空字符串 +   'and CT_OuterCard.VC_OC_Company like ''%'才会正常显示,所以这次PRINT才会有值
 6 SET @CdtSQL = @CdtSQL + 'and CT_OuterCard.VC_OC_Company like ''%'
 7 PRINT @CdtSQL
 8 
 9 
10 --两种写法的比较
11 declare @CdtSQL varchar(max)
12 SET @CdtSQL = ''
13 set @CdtSQL =@CdtSQL + 'and CT_OuterCard.VC_OC_Company like %'
14 print @CdtSQL
15 SET @CdtSQL = ''
16 SET @CdtSQL = @CdtSQL + 'and CT_OuterCard.VC_OC_Company like ''%'
17 PRINT @CdtSQL 

 

posted @ 2013-08-02 21:56 桦仔 阅读(...) 评论(...)  编辑 收藏