SQL查询来获取用户的数据在一排

Question

username skill  mark 

x   writing 10 
x   reading 11 

a   writing 15 
a   reading 14 

我想要得到的O/P是这样的：

x  10 11 
y  15 14 

Answer 1

select username,skill,mark from Your_table;#this fetches only 3 

Or 

select * from Your_table; #this will fetch all fields of your table 

Answer 2

有条件的聚集是要走的路：

SELECT t.username, 
     MAX(CASE WHEN t.skill = 'writing' THEN t.mark END) as writing_mark, 
     MAX(CASE WHEN t.skill = 'reading' THEN t.mark END) as reading_mark 
FROM YourTable t 
GROUP BY t.username