Question

表t2有2列（id，表名），其值分别为（1,2,3）x（toto，titi，tata）：

id|tablename|
1 |toto|
2 |tata|
3 |titi|

我想创建一个将id作为用户变量输入的过程，并执行以下操作：

BEGIN 

 CREATE TABLE `newtable` AS (
 SELECT * FROM (SELECT tablename from t2 WHERE id=2); 
     );
END

结果应表现为查询为：

BEGIN
CREATE TABLE `newtable` AS (
SELECT * FROM `tata`
);
 END

Answer 1

DELIMITER $$

CREATE DEFINER=`root`@`localhost` PROCEDURE `pr_create_table_by_reference`(
    IN `str_new_table_name` VARCHAR(50),
    IN `int_id` INT

)
LANGUAGE SQL
NOT DETERMINISTIC
CONTAINS SQL
SQL SECURITY DEFINER
COMMENT ''
BEGIN

    DECLARE STR_TABLE_NAME VARCHAR(1000) DEFAULT NULL;

    SELECT tablename INTO STR_TABLE_NAME FROM t2 WHERE id = int_id LIMIT 1;

    SET @prep_stmt = CONCAT('CREATE TABLE ', str_new_table_name ,' as ( SELECT * FROM ',  STR_TABLE_NAME , ')');

    PREPARE stmt FROM @prep_stmt; 
    EXECUTE stmt; 
    DEALLOCATE PREPARE stmt;
END

$$

程序调用：

SET @new_table:= 'newTable';
SET @id:= 2;
CALL `pr_create_table_by_reference`(@new_table, @id);

OR 

CALL `pr_create_table_by_reference`('newTable', 2);

如何在过程中将变量设置为“表”？

1 个答案: