MySQL的 - 选择在集团主要项目通过

Question

我有以下查询：

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

    UNION ALL 

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

回报

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 

有两个相同的protocolo（2016000008）不同状态（0,1）。我想显示只有一个的重复protocolo，有一个状态= 1

Answer 1

这是你想要的？

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查询，请在SELECT所有列应该是在GROUP BY或聚集功能，除非你真的知道你在做什么。