问题描述
我正在研究一个执行一些动态 sql 的存储过程.这是我在 4GuysFromRolla.com
I'm working on a stored proc that executes some dynamic sql. Here's the example I found on 4GuysFromRolla.com
CREATE PROCEDURE MyProc (@TableName varchar(255), @FirstName varchar(50), @LastName varchar(50)) AS -- Create a variable @SQLStatement DECLARE @SQLStatement varchar(255) -- Enter the dynamic SQL statement into the -- variable @SQLStatement SELECT @SQLStatement = "SELECT * FROM " + @TableName + "WHERE FirstName = '" + @FirstName + "' AND LastName = '" + @LastName + "'" -- Execute the SQL statement EXEC(@SQLStatement)
如果您注意到,他们使用关键字 SELECT 而不是 SET.我不知道你能做到这一点.有人可以向我解释两者之间的区别吗?我一直认为 SELECT 只是为了选择记录.
If you notice, they are using the keyword SELECT intead of SET. I didn't know you could do this. Can someone explain to me the differences between the 2? I always thought SELECT was simply for selecting records.
推荐答案
SELECT 是 ANSI,SET @LocalVar 是 MS T-SQL
SELECT is ANSI, SET @LocalVar is MS T-SQL
SELECT 允许多个赋值:例如 SELECT @foo = 1, @bar = 2
SELECT allows multiple assignents: eg SELECT @foo = 1, @bar = 2