Question

exec 执行SQL语句问题

declare @username nvarchar(50)set @username='小明'exec('select * from userinfo where ('+@username'='''' or  [user_name]='''+@username+''')')这个是报错的。我想实现的效果是 当@username=''时，查询所有，当@username!=‘’时,查询[user_name]=@username。一定要用exec实现

Answer 1

EXEC sp_executesql @sql 这是语法。你缺东西。
把SQL放在一个变量里。'select * from userinfo where ('+@username'='''' or [user_name]='''+@username+''')'

declare @sql nvarchar(500)
set @sql =''select * from userinfo where ('+@username'='''' or [user_name]='''+@username+''')'

EXEC sp_executesql @sql