Database implementation row and column conversion (Mysql example) _mysql

This article through the SQL sample code to introduce the MySQL database how to achieve row and column conversion, the following words not to say, directly to see the sample code.

Original table:

Table name: User
----------------------------------------
name    | course  | grade
--------------------- -------------------
Zhangsan  | Java   |
----------------------------------------
Zhangsan  | C + +
----------------------------------------
Lisi    | java   |
---------------- ------------------------
Lisi    | C #
----------------------------------------

Use an SQL statement to get the following form:

----------------------------------------
name   | java | C + + | C #----------------------------------------Zhangsan | |-  null
------------------- ---------------------Lisi | |-   NULL |
----------------------------------------

Programme I

Select  name,
sum (case when course= ' Java ' then grade end) as Java,
sum (case when course= ' C + + ' then grade end) a S C + +,
sum (case when course= ' C # ' then grade end) as C # from
test GROUP by name

Programme II

SELECT DISTINCT c. ' Name ' as name,
(select grade from test where name = C. ' name ' and course = ' java ') as Java,
(SE Lect grade from test where name = C. ' name ' and course = ' C + + ') as C + +,
(select grade from test where name = C. ' Name ') and course = ' C # ') as C # from
test C

Summarize

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