我们在同一台服务器上有 100 多个具有相同架构的数据库。我需要在所有数据库上运行相同的 select 语句并返回结果。我查看了几篇关于更改许多数据库的帖子并尝试了这个：
SELECT CONCAT
('SELECT * FROM ', a.table_schema, '.tableIwant
GROUP BY CONCAT(emp_id, "-", other_id)
HAVING count(CONCAT(emp_id, "-", other_id)) >1')
FROM information_schema.tables a
WHERE a.table_schema LIKE 'table_prefix_%'
GROUP BY a.table_schema;
但是所有这些返回的是一个查询列表。我知道我可以使用 PHP 来做到这一点 - 用一个查询构建所有 dbs 的列表，然后在结果集上进行 WHILE 循环等。但我想从 MySQL 做到这一点，有没有办法？
更新：
感谢@KayakJim，我尝试创建一个存储过程来解决这个问题：
DELIMITER //
CREATE PROCEDURE checkDuplicates()
BEGIN
DECLARE bDone INT;
DECLARE dbname VARCHAR(20);
DECLARE count1, count2 INT;
DECLARE curs CURSOR FOR SELECT table_schema FROM INFORMATION_SCHEMA.TABLES WHERE table_schema like 'table_%' GROUP BY table_schema;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET bDone = 1;
CREATE TEMPORARY TABLE IF NOT EXISTS db1.tblResults (
name VARCHAR(20),
countDupes INT,
countDupesAll INT
) ENGINE = MEMORY
;
OPEN curs;
SET bDone = 0;
REPEAT
FETCH curs INTO dbname;
SELECT SQL_CALC_FOUND_ROWS * FROM dbname.table
GROUP BY CONCAT(emp_id, "-", other_id)
HAVING count(CONCAT(emp_id, "-", other_id)) >1;
SET count1 = FOUND_ROWS();
SELECT SQL_CALC_FOUND_ROWS * FROM dbname.table
GROUP BY CONCAT(emp_id, "-", other_id, "-", param)
HAVING count(CONCAT(emp_id, "-", other_id, "-", param)) >1;
SET count2 = FOUND_ROWS();
UNTIL bDone END REPEAT;
CLOSE curs;
SELECT * FROM db1.tblResults;
END;
//
CALL checkDuplicates();
现在的问题是，当我执行时，它返回错误 1049: Unknown database 'information_schema'。当我接受该查询并单独运行它时，我没有收到任何错误，并且它返回与 WHERE 子句匹配的数据库列表。