查詢多個計數語句

Question

我想結合以下兩個查詢，這樣我最終有三列：RelativePath，field = null /空字符串，帶值的字段。我可以單獨執行查詢，但我無法將它們組合起來。

SELECT RELATIVEPATH, COUNT(RELATIVEPATH) FROM APP 
     WHERE (FIELD IS NULL) OR (FIELD = '') 
     GROUP BY (RELATIVEPATH); 

SELECT RELATIVEPATH, COUNT(RELATIVEPATH) FROM APP 
     WHERE (FIELD IS NOT NULL) 
     GROUP BY (RELATIVEPATH); 

Answer 1

您需要case聲明：

SELECT RELATIVEPATH, sum(case when (FIELD IS NULL) OR (FIELD = '') then 1 else 0 end), 
     sum(case when field is not null then 1 else 0 end) 
FROM APP 
GROUP BY (RELATIVEPATH); 

這是假設的count(RelativePath)的目的是計算所有行。如果您真的想要計算列的非NULL值，您可以使用：

SELECT RELATIVEPATH, count(case when (FIELD IS NULL) OR (FIELD = '') then RelativePath end), 
     count(case when field is not null then RelativePath end) 
FROM APP 
GROUP BY (RELATIVEPATH);