如何使用mysql将查询结果存储在变量中

Question

SET @v1 := SELECT COUNT(*) FROM user_rating;
SELECT @v1

当我用set变量执行此查询时,会显示此错误.

Error Code : 1064
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use
near 'SELECT count(*) FROM user_rating' at line 1

Execution Time : 00:00:00:000
Transfer Time  : 00:00:00:000
Total Time     : 00:00:00:000

(1 row(s) returned)
Execution Time : 00:00:00:343
Transfer Time  : 00:00:00:000
Total Time     : 00:00:00:343

Answer 1

用括号选择的环绕声.

SET @v1 := (SELECT COUNT(*) FROM user_rating);
SELECT @v1;

Answer 2

此外,如果要通过一个查询一次设置多个变量,可以使用其他语法设置变量,如下所示:SELECT @varname:=value.

一个实际的例子:

SELECT @total_count:=COUNT(*), @total_price:=SUM(quantity*price) FROM items ...

Answer 3

用这个

 SELECT weight INTO @x FROM p_status where tcount=['value'] LIMIT 1;

测试和工作正常...

Answer 4

Select count(*) from table_name into @var1; 
Select @var1;