MySQL查询帮助作为附加格式

Question

我有一个MySQL表，如下所示：

# Structure for table "audit"
#
DROP TABLE IF EXISTS `audit`;
CREATE TABLE `audit` (
  `Id` int(11) NOT NULL AUTO_INCREMENT,
  `item` varchar(255) DEFAULT NULL,
  `amount` varchar(255) DEFAULT NULL,
  `myDate` date DEFAULT NULL,
  PRIMARY KEY (`Id`)
) ENGINE=InnoDB AUTO_INCREMENT=15 DEFAULT CHARSET=latin1;
#
# Data for table "audit"
#
INSERT INTO `audit` VALUES 
    (1,'audit','0','2015-12-23'),
    (2,'fs_delete','4206','2015-12-23'),
    (3,'log_print','27443','2015-12-23'),
    (4,'sys_error','10102','2015-12-23'),
    (5,'sys_info','150','2015-12-23'),
    (6,'sys_proxy','30','2015-12-23'),
    (7,'users','2','2015-12-23'),
    (8,'audit','7','2015-12-22'),
    (9,'fs_delete','4206','2015-12-22'),
    (10,'log_print','27443','2015-12-22'),
    (11,'sys_error','10102','2015-12-22'),
    (12,'sys_info','150','2015-12-22'),
    (13,'sys_proxy','30','2015-12-22'),
    (14,'users','2','2015-12-22');

我想输出如下图所示

Answer 1

我认为您需要这样的查询：

SELECT `myDate`
    , MAX(CASE WHEN `item` = 'audit' THEN `amount` END) AS `audit`
    , MAX(CASE WHEN `item` = 'fs_delete' THEN `amount` END) AS `fs_delete`
    , MAX(CASE WHEN `item` = 'log_print' THEN `amount` END) AS `log_print`
    , MAX(CASE WHEN `item` = 'sys_error' THEN `amount` END) AS `sys_error`
    , MAX(CASE WHEN `item` = 'sys_info' THEN `amount` END) AS `sys_info`
FROM `audit`
GROUP BY `myDate`;

[SQL Fiddle Demo]