mysql 行列转换方式

1，decode函数

   select t.user_name,

     sum(decode(t.course, '语文', score,null)) as CHINESE,

     sum(decode(t.course, '数学', score,null)) as MATH,

     sum(decode(t.course, '英语', score,null)) as ENGLISH

   from test_tb_grade t

    group by t.user_name

   order by t.user_name

 

2、if函数

select t.date,

 sum(if(pay_type='1',num,0)) unionPay,

 sum(if(pay_type='2',num,0)) alipay,

 sum(if(pay_type='5',num,0)) activeCard,

 sum(if(pay_type='7',num,0)) weChat 

 from t

group by t.date