MySQL的 - 選擇在集團主要項目通過

Question

我有以下查詢：

SELECT * FROM (
    SELECT codigo, protocolo, status, nome 
    FROM protocolo 
    GROUP BY protocolo.protocolo 

    UNION ALL 

    SELECT codigo, protocolo, status, nome 
    FROM simulador 
) tabela 

回報

codigo protocolo status nome 
559  2016000026 1  ALESSANDRO CAMPOS BONIFACIO 
0  2016000026 0  ALESSANDRO CAMPOS BONIFACIO 
0  2016000008 0  MARIA DE JESUS F. DA SILVA *** 
0  2016000007 0  MARGARIDA BORGES DA SILVA 
558  2016000008 1  MARIA DE JESUS F. DA SILVA *** 
556  2015014035 1  MARIA DALVA DA SILVA 

有兩個相同的protocolo（2016000008）不同狀態（0,1）。我想顯示只有一個的重複protocolo，有一個狀態= 1

Answer 1

這是你想要的？

SELECT odigo, protocolo, MAX(status) as stat, nome 
FROM (
    SELECT codigo, protocolo, status, nome 
    FROM protocolo 
    GROUP BY protocolo.protocolo 

    UNION ALL 

    SELECT codigo, protocolo, status, nome 
    FROM simulador 
) tabela 
GROUP BY codigo, protocolo, nome ; 

注：在GROUP BY查詢，請在SELECT所有列應該是在GROUP BY或聚集功能，除非你真的知道你在做什麼。