MySQL 动态行转列

CREATE TABLE `tbl01` (

`id` INT(11) DEFAULT NULL,

`kemu` VARCHAR(20) COLLATE utf8_unicode_ci DEFAULT NULL

) ENGINE=INNODB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci

INSERT INTO tbl01(id, kemu) VALUES ('1', '语文');

INSERT INTO tbl01(id, kemu) VALUES ('2', '数学');

INSERT INTO tbl01(id, kemu) VALUES ('3', '英语');

INSERT INTO tbl01(id, kemu) VALUES ('4', '物理');

INSERT INTO tbl01(id, kemu) VALUES ('5', '化学');

CREATE TABLE `tbl02` (

`nid` VARCHAR(20) COLLATE utf8_unicode_ci DEFAULT NULL,

`kemu` VARCHAR(20) COLLATE utf8_unicode_ci DEFAULT NULL,

`chji` INT(11) DEFAULT NULL

) ENGINE=INNODB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci

INSERT INTO tbl02 (nid, kemu, chji) VALUES ('李明', '1', '95');

INSERT INTO tbl02 (nid, kemu, chji) VALUES ('李明', '2', '89');

INSERT INTO tbl02 (nid, kemu, chji) VALUES ('李明', '4', '74');

INSERT INTO tbl02 (nid, kemu, chji) VALUES ('张三', '1', '81');

INSERT INTO tbl02 (nid, kemu, chji) VALUES ('张三', '3', '65');

INSERT INTO tbl02 (nid, kemu, chji) VALUES ('张三', '5', '38');

SET @sql := 'SELECT nid';

SELECT @sql := CONCAT(@sql, ', max(case kemu when ', id, ' then chji else 0 end) as ', kemu)

FROM (SELECT DISTINCT id, kemu FROM tbl01) AS a;

SELECT @sqlstr := CONCAT(@sql, ' from tbl02 group by nid');

PREPARE rc FROM @sqlstr;

EXECUTE rc;

统计每个人各年级的总成绩：

SET @sql := 'SELECT xm';

SELECT @sql := CONCAT(@sql, ', sum(case nj when ', nj, ' then cj else 0 end) as `', nj, '年级`')

FROM (SELECT nj FROM tbl03 GROUP BY nj) AS a;

SELECT @sqlstr := CONCAT(@sql, ' from tbl03 group by xm');

PREPARE rc FROM @sqlstr;

EXECUTE rc;