mysql - 对所有表执行查询并在新表中填充数据

Question

我需要得到包含字段的结果表 - 表名、最小日期、最大日期

这是我的查询，我应该对所有表执行该查询

SELECT MIN(short_date) as FirstDuplicatedDate, MAX(short_date) as LastDuplicatedDate
FROM (SELECT  short_date, type, value,  count(*) as cnt
FROM testTable
GROUP BY  short_date
HAVING COUNT(*) > 1) as Duplicates

然后我发现了如何获取所有表名我是这样做的

SELECT TABLE_NAME as name FROM `information_schema`.`TABLES`
WHERE `TABLES`.`TABLE_SCHEMA` = 'test'
AND `TABLES`.`TABLE_NAME` LIKE 'test%'

但我不知道如何对所有表执行它并将结果填充到新表中。

我试过这样做

DECLARE @DB_Name varchar(50)
DECLARE @Command varchar(100);
DECLARE database_cursor CURSOR FOR 
SELECT name 
FROM (SELECT TABLE_NAME as name FROM `information_schema`.`TABLES`
WHERE `TABLES`.`TABLE_SCHEMA` = 'test'
AND `TABLES`.`TABLE_NAME` LIKE 'test%') as TableNames

OPEN database_cursor

FETCH NEXT FROM database_cursor INTO @DB_Name

WHILE @@FETCH_STATUS = 0 
BEGIN 
     SELECT @Command = 'SELECT MIN(short_date) as FirstDuplicatedDate, MAX(short_date) as LastDuplicatedDate
FROM (SELECT  short_date, type, value,  count(*) as cnt
FROM ' + @DB_Name + '
WHERE type = ''test''
GROUP BY  short_date, type, value
HAVING COUNT(*) > 1) as Duplicates'
     EXEC sp_executesql @Command

     FETCH NEXT FROM database_cursor INTO @DB_Name 
END

CLOSE database_cursor 
DEALLOCATE database_cursor

但是我得到了这个错误

Syntax error or access violation: 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 'DECLARE @DB_Name varchar(50) DECLARE @Command varchar(100)' at line 1

UPD

CREATE PROCEDURE GetData()
BEGIN

DECLARE @DB_Name varchar(50), @Command varchar(100);
DECLARE database_cursor CURSOR FOR 
SELECT name 
FROM (SELECT TABLE_NAME as name FROM `information_schema`.`TABLES`
WHERE `TABLES`.`TABLE_SCHEMA` = 'test'
AND `TABLES`.`TABLE_NAME` LIKE 'test%_') as TableNames

OPEN database_cursor

FETCH NEXT FROM database_cursor INTO @DB_Name

WHILE @@FETCH_STATUS = 0 
BEGIN 
     SELECT @Command = 'SELECT MIN(short_date) as FirstDuplicatedDate, MAX(short_date) as LastDuplicatedDate
FROM (SELECT  short_date, type, value,  count(*) as cnt
FROM ' + @DB_Name + '
WHERE type = ''test''
GROUP BY  short_date, type, value
HAVING COUNT(*) > 1) as Duplicates'
     EXEC sp_executesql @Command

     FETCH NEXT FROM database_cursor INTO @DB_Name 
END;

CLOSE database_cursor 
DEALLOCATE database_cursor

END;

CALL GetData()

Answer 1

在开头添加DELIMITER $$；在 END 之后添加 DELIMITER ;。

摆脱声明命令。而是使用不需要声明的 @command。

在 SELECT @command := ...; 之后添加 SELECT @command; 以便我们进行一些调试。

CLOSE 和DEALLOCATE 语句需要; 来终止它们。

测试用完要FETCH 的行。

您确实需要查看一些存储过程示例，尤其是那些带有游标的示例。

更新

呃，我什至没有发现一半的语法错误。这可能有效(我不知道，因为我没有您的特定表格或列。):

DROP PROCEDURE IF EXISTS so42856538;

DELIMITER $$

CREATE PROCEDURE so42856538()
    LANGUAGE SQL
    MODIFIES SQL DATA
    SQL SECURITY INVOKER
BEGIN

DECLARE _TableName varchar(64);
DECLARE _done INT DEFAULT FALSE;
DECLARE database_cursor CURSOR FOR 
    SELECT TABLE_NAME
        FROM `information_schema`.`TABLES`
        WHERE `TABLE_SCHEMA` = 'test'
          AND `TABLE_NAME` LIKE 'test%';
DECLARE CONTINUE HANDLER FOR NOT FOUND SET _done = TRUE;

OPEN database_cursor;
curs_loop: LOOP
    FETCH NEXT FROM database_cursor INTO _TableName;
    IF _done THEN  LEAVE curs_loop;  END IF;
    SET @Command := CONCAT(
           'SELECT MIN(short_date) as FirstDuplicatedDate,
                           MAX(short_date) as LastDuplicatedDate
           FROM ( SELECT  short_date, type, value,  count(*) as cnt
                    FROM ', _TableName, '
                    WHERE type = "test"
                    GROUP BY  short_date, type, value
                    HAVING COUNT(*) > 1 ) as Duplicates'
                        );
    SELECT _TableName, @command;   -- Debugging (remove if it is clutter)
    PREPARE _sql FROM @command;
    EXECUTE _sql;
    DEALLOCATE PREPARE _sql;
END LOOP;
CLOSE database_cursor;

END $$

DELIMITER ;

CALL so42856538;