SQL语句中，横向记录转成纵向列， 纵向列转成横向记录。 无 ##############行转列-example 1 ,学生成绩###############创建数据库表CREATE TABLE StudentScores ( UserName NVARCHAR(20), Subject NVARCHAR(30), Score FLOAT ) ; #插入模拟数据INSERT INTO St
SQL语句中，横向记录转成纵向列， 纵向列转成横向记录。
##############行转列-example 1 ,学生成绩##############
#创建数据库表
CREATE TABLE StudentScores (
UserName NVARCHAR(20),
Subject NVARCHAR(30),
Score FLOAT
) ;
#插入模拟数据
INSERT INTO StudentScores SELECT 'Nick', '语文', 80 ;
INSERT INTO StudentScores SELECT 'Nick', '数学', 90 ;
INSERT INTO StudentScores SELECT 'Nick', '英语', 70 ;
INSERT INTO StudentScores SELECT 'Nick', '生物', 85 ;
INSERT INTO StudentScores SELECT 'Kent', '语文', 80 ;
INSERT INTO StudentScores SELECT 'Kent', '数学', 90 ;
INSERT INTO StudentScores SELECT 'Kent', '英语', 70 ;
INSERT INTO StudentScores SELECT 'Kent', '生物', 85 ;
#查询每个学生的各科成绩
SELECT UserName,
MAX(CASE Subject WHEN '语文' THEN Score ELSE 0 END) AS '语文',
MAX(CASE Subject WHEN '数学' THEN Score ELSE 0 END) AS '数学',
MAX(CASE Subject WHEN '英语' THEN Score ELSE 0 END) AS '英语',
MAX(CASE Subject WHEN '生物' THEN Score ELSE 0 END) AS '生物'
FROM StudentScores
GROUP BY UserName ;
##############行转列-example 2 ,游戏玩家充值##############
#创建数据库表
CREATE TABLE Inpours (
ID INT AUTO_INCREMENT,
UserName NVARCHAR(20),
CreateTime DATETIME,
PayType NVARCHAR(20),
Money DECIMAL,
IsSuccess BIT,
CONSTRAINT PK_Inpours_ID PRIMARY KEY(ID)
) ;
#插入模拟数据
INSERT INTO Inpours(UserName , CreateTime , PayType , Money , IsSuccess) SELECT '张三', '2010-05-01', '支付宝', 50, 1 ;
INSERT INTO Inpours(UserName , CreateTime , PayType , Money , IsSuccess) SELECT '张三', '2010-06-14', '支付宝', 50, 1 ;
INSERT INTO Inpours(UserName , CreateTime , PayType , Money , IsSuccess) SELECT '张三', '2010-06-14', '手机短信', 100, 1 ;
INSERT INTO Inpours(UserName , CreateTime , PayType , Money , IsSuccess) SELECT '李四', '2010-06-14', '手机短信', 100, 1 ;
INSERT INTO Inpours(UserName , CreateTime , PayType , Money , IsSuccess) SELECT '李四', '2010-07-14', '支付宝', 100, 1 ;
INSERT INTO Inpours(UserName , CreateTime , PayType , Money , IsSuccess) SELECT '王五', '2010-07-14', '工商银行卡', 100, 1 ;
INSERT INTO Inpours(UserName , CreateTime , PayType , Money , IsSuccess) SELECT '赵六', '2010-07-14', '建设银行卡', 100, 1 ;
#要求按日期、支付方式来统计充值金额信息
select CreateTime,
CASE PayType WHEN '支付宝' THEN SUM(Money) ELSE 0 END AS '支付宝',
CASE PayType WHEN '手机短信' THEN SUM(Money) ELSE 0 END AS '手机短信',
CASE PayType WHEN '工商银行卡' THEN SUM(Money) ELSE 0 END AS '工商银行卡',
CASE PayType WHEN '建设银行卡' THEN SUM(Money) ELSE 0 END AS '建设银行卡'
FROM Inpours
GROUP BY CreateTime, PayType
##############列转行-example 1 ,供货信息##############
#创建数据库表
CREATE TABLE ProgrectDetail (
ProgrectName NVARCHAR(20),
OverseaSupply INT,
NativeSupply INT,
SouthSupply INT,
NorthSupply INT
)
#插入模拟数据
INSERT INTO ProgrectDetail
SELECT 'A', 100, 200, 50, 50
UNION ALL SELECT 'B', 200, 300, 150, 150
UNION ALL SELECT 'C', 159, 400, 20, 320
UNION ALL SELECT 'D', 250, 30, 15, 15
#
SELECT ProgrectName, 'OverseaSupply' AS Supplier, MAX(OverseaSupply) AS 'SupplyNum' FROM ProgrectDetail GROUP BY ProgrectName
UNION ALL
SELECT ProgrectName, 'NativeSupply' AS Supplier, MAX(NativeSupply) AS 'SupplyNum' FROM ProgrectDetail GROUP BY ProgrectName
UNION ALL
SELECT ProgrectName, 'SouthSupply' AS Supplier, MAX(SouthSupply) AS 'SupplyNum' FROM ProgrectDetail GROUP BY ProgrectName
UNION ALL
SELECT ProgrectName, 'NorthSupply' AS Supplier, MAX(NorthSupply) AS 'SupplyNum' FROM ProgrectDetail GROUP BY ProgrectName
