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One 、 Data preparation

Here's the data , Student id, Course , fraction

1,yuwen,43
1,shuxue,55
2,yuwen,77
2,shuxue,88
3,yuwen,98
3,shuxue,65

Two 、 Demand analysis

1、 Create table

create table requirement( sid int, course string, score int)row format delimited fields terminated by ',';

2、 Upload data

load data local inpath '/usr/mydir/data/requirement.txt' into table requirement;

3、 Verify that the data is correct

select * from requirement;

4、 Query data

Method 1 ：

select sid, max(math) as math, max(chinese) as chinese from (select *, case course when 'shuxue' then score else 0 end .........