MySQL选择成变量 [英] MySQL Select into variable

问题描述

我想在过程中进一步使用从选择中获得的值，然后执行，但不知道如何执行.

I want to further use in the procedure the values I get from a select into execution but can't figure out how to do it.

作为测试，我编写了以下内容，但不能将v_1，v_2或v_3变量用于进一步的逻辑，因为它们不采用值1,2&.正如我所期望的3 ...

As a test I wrote the following but cannot use the v_1, v_2 or v_3 variables for further logic as they don't take the values 1,2 & 3 as i expected...

DROP PROCEDURE IF EXISTS MPT_testing; DELIMITER //  CREATE PROCEDURE MPT_testing() READS SQL DATA BEGIN

  DECLARE v_1 INT;   DECLARE v_2 INT;   DECLARE v_3 INT;
     SET @sql=CONCAT('SELECT 1,2 into v_1, v_2');   PREPARE s1 FROM @sql;   EXECUTE s1;   DEALLOCATE PREPARE s1;

  SET v_3 = v_1 + v_2;

  SELECT v_3;

END //

DELIMITER ;

有人可以在这里帮忙吗?

Can somebody help here please?

谢谢， 狮子座

推荐答案

尝试将"SELECT 1,2更改为v_1，v_2"至

Try changing 'SELECT 1,2 into v_1, v_2' to

'SELECT @v_1:=1, @v_2:=2'

或至少确保在引用变量时使用@.有关更多信息，请参见此线程: 在MySQL DECLARE中选择INTO变量会导致语法错误?

or at least make sure you use @ whenever referencing your vars. see this thread for more info: SELECT INTO Variable in MySQL DECLARE causes syntax error?

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