使用mysql Prepared语句执行多个用分号分隔的查询 [英] Execute multiple semi-colon separated query using mysql Prepared Statement

问题描述

我试图在mysql中创建一个存储过程，该存储过程会在每个请求上创建一个新表，并从另一个表中复制内容，并提取所需的数据，最后删除该表.存储过程很大，因此在每次查询后我都无法执行，因此我试图以分号分隔的格式一起执行查询.但是在最终执行时，我得到错误代码:1064. 我尝试的方法是否可行，还是有更好的方法.

I am trying to create a stored procedure in mysql which creates a new table on every request copies the content from another table and extracts the required data and finally drops the table. The stored procedure is quite large so I cant have EXECUTE after every query and thus I am trying to execute the query all together in a semicolon separated format. But on final execution I get Error Code: 1064. Is the approach I am trying possible, or is there a better approach.

SET tableName = (SELECT CONCAT("table",(UNIX_TIMESTAMP(NOW()))));

SET @tquery =CONCAT('CREATE TABLE `',tableName,'` (select pt.* from post_table pt join on user u on pt.user_id=u.id where pt.client="client",pt.group="group");');
SET @tquery = CONCAT(@tquery,' SELECT * FROM ',tableName,';');    
SET @tquery = CONCAT(@tquery,' DROP TABLE ',tableName,';');    
PREPARE stmt FROM @tquery;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;  

推荐答案

否，这是不可能的. PREPARE / EXECUTE stmt一次只能执行一个查询，许多语句不能合并.
请参见文档: http://dev.mysql.com/doc /refman/5.0/en/prepare.html

No, it is not possible. PREPARE / EXECUTE stmt can execute only one query at a time, many statements cannot be combined.
See documentation: http://dev.mysql.com/doc/refman/5.0/en/prepare.html

...一个包含SQL语句文本的用户变量.文本必须表示单个语句，而不是多个语句.

无论如何，为了简化您的代码，我将创建一个简单的过程:

Anyway, to simplify your code I would create a simple procedure:

CREATE PROCEDURE exec_qry( p_sql varchar(100))
BEGIN
  SET @tquery = p_sql;
  PREPARE stmt FROM @tquery;
  EXECUTE stmt;
  DEALLOCATE PREPARE stmt;
END 
/

我将以这种方式在主过程中调用此过程:

and I would call this procedure in the main procedure, in this way:

CALL exec_qry( 'CREATE TABLE t2 AS SELECT * FROM test');
CALL exec_qry( 'SELECT * FROM t2');
CALL exec_qry( 'SELECT count(*) FROM t2');
CALL exec_qry( 'SELECT avg(x) FROM t2');
CALL exec_qry( 'DROP TABLE t2');

看一下演示: http://www.sqlfiddle.com/# ！2/6649a/6

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