SELECT @v = OperateCode SELECT赋值


Warning: Undefined array key "HTTP_REFERER" in /www/wwwroot/prod/www.enjoyasp.net/wp-content/plugins/google-highlight/google-hilite.php on line 58
declare @v varchar(500)
set @v = ''
    SELECT  @v =  OperateCode 
        FROM
        (    
            SELECT 'd' operatecode
            union  all select 'e'
                
        ) T1
select @v
结果为 ‘e’ 即:这种赋值方式会遍历所有记录,将记录一一赋给@v,@v的值为最后一个。可利用这一特性,将一列转换到一格中存储
declare @v varchar(500)
set @v = ''
    SELECT  @v =  @v + OperateCode + ‘,’
        FROM
        (    
            SELECT 'd' operatecode
            union  all select 'e'
                
        ) T1
select @v
结果为:d,e