Question

我有以下MySQL脚本，但它不起作用。当我从IF（INSERT INTO之后）删除第二个查询（SELECT）时，它开始工作。我的问题是：我可以在准备好的声明中执行多个查询但不能使用过程（最后一部分是我为此开设新问题的原因）？

提前致谢...

SQL：

SET @data1 = 'DATA_HERE' COLLATE utf8_general_ci
;

/* Random key */
SET @randomKey = CONCAT( 'rnd', DATE_FORMAT(NOW(), '%Y%m%d') , FLOOR( RAND() * 100 ) ) COLLATE utf8_general_ci
;

/* If not exists do an INSERT else SELECT a warning message */
SET @stmt = IF(
        ( SELECT EXISTS (
                SELECT
                    t0.id
                FROM
                    table t0
                WHERE 1
                    AND t0.key = @randomKey COLLATE utf8_general_ci
                    AND t0.data = @data1 COLLATE utf8_general_ci
            )
        ) = 0
        , CONCAT( "
            INSERT INTO
                table
            SET
                key = @randomKey COLLATE utf8_general_ci
                , data = @data1 COLLATE utf8_general_ci;

            SELECT
                t0.*
            FROM
                table t0
            WHERE 1
                AND t0.id = LAST_INSERT_ID(); " 
        )
        , CONCAT( "SELECT CONCAT( 'This random key already exists with this data!' );" )
    )
;

PREPARE stmt FROM @stmt
;
EXECUTE stmt
;

Answer 1

如果您的表格刚刚调用t0，那么您就不需要说table t0。只需使用SELECT * FROM t0 WHERE /* your predicate */

即可

MySQL准备语句中的多个查询（无过程）

1 个答案: