连接多个表，条件语句

Question

我有3个MySQL表是这样的：

基于该表我想打一个表，条件语句： 如果从表3郭尔> =然后nilai saran =表2中的市长和未成年人，否则saran =表1中值大于0的butuh和bidang的concat。而对于汝=

selct((max(skor)-min(skor))*0.25)+min(skor) from table 3 

所以，这样的结果：

如何做呢？

Answer 1

尝试以下查询：

select 
NIP, 
Bidang, 
case when Skor >= ((max(skor)-min(skor))*0.25)+min(skor) 
then concat(mayor,',',minor) 
else concat(Butuh,',',Bidang) 
end as Saran 
from 
(
select table2.*, 
table1.Butuh, 
table1.Kurang, 
table3.Skor 
from table2 join table1 
on table2.Bidang = table1.Bidang 
left join table3 
on table2.NIP = table3.NIP 
where table1.Butuh > 0 
) tab 

Answer 2

假设nilai只是意味着一个全球性的分数门槛，你基本上要...

• 建立一个聚合的nilai值的查询
• 将来自不同记录的汇总数据转换为单个字符串
• 连接表和汇总查询
• 选择所需的数据，应用函数根据需要创建适当的输出。

你的结果将沿着以下的说法：

select t2.Nip 
    , t3.bidang 
    , case when t3.skor >= t3disc.nilai then t2.mayor || ', ' || t2.minor else base_1.butuh_agg end 
        saran 
    from table_2 t2 
    join table_3 t3 on (t3.Nip = t2.Nip and t3.bidang = t2.bidang) 
    join (
       select t11.bidang 
        , t11.butuh 
         || CASE WHEN t12.butuh IS NOT NULL THEN ', ' || t12.butuh ELSE '' END 
         || CASE WHEN t13.butuh IS NOT NULL THEN ', ' || t13.butuh ELSE '' END 
         || CASE WHEN t14.butuh IS NOT NULL THEN ', ' || t14.butuh ELSE '' END 
         || CASE WHEN t15.butuh IS NOT NULL THEN ', ' || t15.butuh ELSE '' END 
          butuh_agg 
        from (
          select t1.bidang 
           , min(t1.kurang) kmin 
           from table_1 t1 
          group by t1.bidang 
         ) t11 
      left join table_1 t12 on (t12.bidang = t11.bidang AND t12.kurang = t11.kmin + 1) 
      left join table_1 t13 on (t13.bidang = t11.bidang AND t13.kurang = t11.kmin + 2) 
      left join table_1 t14 on (t14.bidang = t11.bidang AND t14.kurang = t11.kmin + 3) 
      left join table_1 t15 on (t15.bidang = t11.bidang AND t15.kurang = t11.kmin + 4) 
     ) base_1 on (base_1.bidang = t2.bidang) 
    join (
       select t31.bidang 
        , t3agg.nilai 
       from table_3 t31 
      cross join (
         select (max(t32.skor) - min(t32.skor)) * 0.25) + min(t32.skor) nilai 
          from table_3 t32 
        ) t3agg 
     ) t3disc on (t3disc.bidang = t2.bidang) 
     ; 

此建议假定你有最大的在表1中的任何给定的bidang 4非零值，有其中不存在重复值，并且这些值小于或等于4.否则，您将不得不求助于查询中的排名函数。