常用sql功能

横纵表互转

select n.name,sum(case course when '语文' then grade else 0 end) as 语文,sum(case course when '数学' then grade else 0 end) as 数学,sum(case course when '英语' then grade else 0 end) as 英语from diy.new_table as ngroup by name;

SELECT   name,'语文'   AS     科目,语文   AS   成绩   FROM   new_table1   UNION   ALL SELECT   name,'数学'   AS     科目,数学   AS   成绩   FROM   new_table1   UNION   ALL SELECT   name,'英语'   AS     科目,英语   AS   成绩   FROM   new_table1ORDER BY name,科目 DESC;

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