mysql 存储过程连接不同数据库写法

BEGIN

set @sql=concat(‘select * from ‘,db_name,’.’,‘elle_transin ‘,’ where id=4’);

PREPARE stm FROM @sql;
EXECUTE stm;
DEALLOCATE PREPARE stm;

END

调用

jessiejane
CALL _david_test(‘jessiejane’);
用contact函数拼接字符串
prepare 准备sql 赋给stm
再用execute 执行 被赋值的sql
最后释放 执行的sql stm