请教一个问题，谢谢帮助
- SQL code
表aaid name mc1 mc1sl mc2 mc2sl mc3 mc3sl1 '张三' '铅笔' '20' '毛笔' '40' '卷尺' '50'2 '李四' '毛笔' '20' '钢笔' '40' '直尺' '50'表bbid name pname1 '钢笔' '笔'2 '毛笔' '笔'3 '铅笔' '笔'4 '卷尺' '尺'5 '直尺' '尺'输出结果 笔 尺aid a.name 铅笔 毛笔 钢笔 直尺 卷尺1 '张三' 20 40 0 50 01 '李四' 0 20 40 0 50
[解决办法]
- SQL code
select aid,name,case when mc1='铅笔' then mc1slwhen mc2='铅笔' then mc2sl when mc3='铅笔' then mc3slelse 0 end "铅笔" ,case when mc1='毛笔' then mc1slwhen mc2='毛笔' then mc2sl when mc3='毛笔' then mc3slelse 0 end "毛笔" ,case when mc1='钢笔' then mc1slwhen mc2='钢笔' then mc2sl when mc3='钢笔' then mc3slelse 0 end "钢笔" ,case when mc1='卷尺' then mc1slwhen mc2='卷尺' then mc2sl when mc3='卷尺' then mc3slelse 0 end "卷尺" ,case when mc1='直尺' then mc1slwhen mc2='直尺' then mc2sl when mc3='直尺' then mc3slelse 0 end "直尺" from a/*aid name 铅笔 毛笔 钢笔 卷尺 直尺1 张三 20 40 0 50 02 李四 0 20 40 0 50