連接多個表，條件語句

Question

我有3個MySQL表是這樣的：

基於該表我想打一個表，條件語句： 如果從表3郭爾> =然後nilai saran =表2中的市長和未成年人，否則saran =表1中值大於0的butuh和bidang的concat。而對於汝=

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

所以，這樣的結果：

如何做呢？

Answer 1

嘗試以下查詢：

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

假設nilai只是意味着一個全球性的分數門檻，你基本上要...

• 建立一個聚合的nilai值的查詢
• 將來自不同記錄的彙總數據轉換爲單個字符串
• 連接表和彙總查詢
• 選擇所需的數據，應用函數根據需要創建適當的輸出。

你的結果將沿着以下的說法：

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) 
     ; 

此建議假定你有最大的在表1中的任何給定的bidang 4非零值，有其中不存在重複值，並且這些值小於或等於4.否則，您將不得不求助於查詢中的排名函數。