mysql查询输出正确，算错了

Question

SELECT 
    count(A.gross_c) AS cnt, 
    SUM(A.gross_c) AS Gross_c, 
    B.store_name
FROM hr_location_c_verified A 
JOIN hr_stores B ON A.c_location = B.id
WHERE A.c_ref_fkid IS NULL
GROUP BY A.c_location

我正在执行此查询，输出结果正确，但计数显示错误。

请帮帮我。

Answer 1

可能是因为你的 JOIN ，会产生更多行。

一种方法是使用 DISTINCT 关键字。

SELECT 
    count(DISTINCT A.gross_c) AS cnt, 
    SUM(A.gross_c) AS Gross_c, 
    B.store_name FROM hr_location_c_verified A 
JOIN hr_stores B ON A.c_location = B.id
WHERE A.c_ref_fkid IS NULL
GROUP BY A.c_location