常用sql

摘要: 常用sql

SELECT
broswer NAME,
count(1) VALUE ,
CASE
WHEN broswer = 'Firefox' THEN '#FF00FF'
WHEN broswer = 'IE' THEN '#FFFF00'
ELSE '#43CD80'
END color
FROM
t_s_log
GROUP BY
broswer

======================行列转换=====================
CREATE TABLE `table_name` (
`id` int(11) NOT NULL,
`col1` char(2) DEFAULT NULL,
`col2` char(2) DEFAULT NULL,
`col3` int(11) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

insert into table_name values (1 ,'A1','B1',9), (2 ,'A2','B1',7), (3 ,'A3','B1',4), (4 ,'A4','B1',2),
(5 ,'A1','B2',2), (6 ,'A2','B2',9), (7 ,'A3','B2',8), (8 ,'A4','B2',5), (9 ,'A1','B3',1), (10 ,'A2','B3',8),
(11 ,'A3','B3',8), (12 ,'A4','B3',6), (13 ,'A1','B4',8), (14 ,'A2','B4',2), (15 ,'A3','B4',6), (16 ,'A4','B4',9),
(17 ,'A1','B4',3), (18 ,'A2','B4',5), (19 ,'A3','B4',2), (20 ,'A4','B4',5);

SELECT
ifnull(col1, 'total') AS col1,
sum(IF(col2 = 'B1', col3, 0)) AS B1,
sum(IF(col2 = 'B2', col3, 0)) AS B2,
sum(IF(col2 = 'B3', col3, 0)) AS B3,
sum(IF(col2 = 'B4', col3, 0)) AS B4,
SUM(col3) AS TOTAL
FROM
table_name
GROUP BY
col1 WITH ROLLUP;



=======================1======================

DROP TABLE IF EXISTS `student`;
CREATE TABLE `student` (
`id` bigint(20) NOT NULL AUTO_INCREMENT,
`stu_name` varchar(40) DEFAULT NULL,
`stu_score` double(20,0) DEFAULT NULL,
`class_id` bigint(20) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=20 DEFAULT CHARSET=utf8;

INSERT INTO `student` VALUES ('1', '赵云', '20', '1');
INSERT INTO `student` VALUES ('2', '张飞', '30', '1');
INSERT INTO `student` VALUES ('3', '关羽', '30', '1');
INSERT INTO `student` VALUES ('4', '刘备', '40', '1');
INSERT INTO `student` VALUES ('5', '曹操', '40', '2');
INSERT INTO `student` VALUES ('6', '许褚', '30', '2');
INSERT INTO `student` VALUES ('8', '荀彧', '28', '2');
INSERT INTO `student` VALUES ('9', '荀攸', '29', '2');
INSERT INTO `student` VALUES ('10', '郭嘉', '24', '2');
INSERT INTO `student` VALUES ('11', '诸葛亮', '39', '1');
INSERT INTO `student` VALUES ('12', '孙权', '40', '3');
INSERT INTO `student` VALUES ('13', '孙权', '38', '3');
INSERT INTO `student` VALUES ('14', '孙坚', '31', '3');
INSERT INTO `student` VALUES ('15', '小乔', '20', '3');
INSERT INTO `student` VALUES ('16', '大桥', '20', '3');
INSERT INTO `student` VALUES ('17', '鲁肃', '34', '3');
INSERT INTO `student` VALUES ('18', '陆逊', '31', '3');
INSERT INTO `student` VALUES ('19', '吕蒙', '31', '3');

SELECT * FROM
(
SELECT IFNULL(class_id,'总计') as classid,SUM(stu_score) as score FROM student GROUP BY class_id WITH ROLLUP
) A
ORDER BY score