Question

我有这个代码，我想最小化它，但没有什么对我有用：

SELECT(SELECT COUNT(nes) FROM general_list WHERE nes<>0 AND saga LIKE '%/FFI/%')+
(SELECT COUNT(snes) FROM general_list WHERE snes<>0 AND saga LIKE '%/FFI/%')+
(SELECT COUNT(msx2) FROM general_list WHERE msx2<>0 AND saga LIKE '%/FFI/%')+
(SELECT COUNT(gb) FROM general_list WHERE gb<>0 AND saga LIKE '%/FFI/%')+
(SELECT COUNT(gc) FROM general_list WHERE gc<>0 AND saga LIKE '%/FFI/%')+
(SELECT COUNT(gba) FROM general_list WHERE gba<>0 AND saga LIKE '%/FFI/%')+
(SELECT COUNT(ds) FROM general_list WHERE ds<>0 AND saga LIKE '%/FFI/%')+
(SELECT COUNT(ds3) FROM general_list WHERE ds3<>0 AND saga LIKE '%/FFI/%')+
(SELECT COUNT(wii) FROM general_list WHERE wii<>0 AND saga LIKE '%/FFI/%')+
(SELECT COUNT(pc) FROM general_list WHERE pc<>0 AND saga LIKE '%/FFI/%')+
(SELECT COUNT(ps1) FROM general_list WHERE ps1<>0 AND saga LIKE '%/FFI/%')+
(SELECT COUNT(ps2) FROM general_list WHERE ps2<>0 AND saga LIKE '%/FFI/%')+
(SELECT COUNT(ps3) FROM general_list WHERE ps3<>0 AND saga LIKE '%/FFI/%')+
(SELECT COUNT(ps4) FROM general_list WHERE ps4<>0 AND saga LIKE '%/FFI/%')+
(SELECT COUNT(psp) FROM general_list WHERE psp<>0 AND saga LIKE '%/FFI/%')+
(SELECT COUNT(wsc) FROM general_list WHERE wsc<>0 AND saga LIKE '%/FFI/%')+
(SELECT COUNT(x360) FROM general_list WHERE x360<>0 AND saga LIKE '%/FFI/%')+
(SELECT COUNT(xone) FROM general_list WHERE xone<>0 AND saga LIKE '%/FFI/%') AS SumCount;

我尝试使用SELECT nes，snes，msx2 .......，COUNT（*）并将列放在COUNT中（SELECT COUNT（nes，snes .....）...），但它们都不起作用：（

非常感谢！

Answer 1

您需要条件聚合。这是一个开始：

SELECT (COUNT(CASE WHEN nes <> 0 AND saga LIKE '%/FFI/%' THEN nes END) +
        COUNT(CASE WHEN snes<>0 AND saga LIKE '%/FFI/%' THEN snes END) +
        COUNT(CASE WHEN msx2<>0 AND saga LIKE '%/FFI/%' THEN msx2 END) +
        . . .
       ) as SumCount
FROM general_list;

鉴于saga片段完全相同，您可以将其简化为：

SELECT (COUNT(CASE WHEN nes <> 0 THEN nes END) +
        COUNT(CASE WHEN snes <> 0 THEN snes END) +
        COUNT(CASE WHEN msx2 <> 0 THEN msx2 END) +
        . . .
       ) as SumCount
FROM general_list
WHERE saga LIKE '%/FFI/%' ;

而且，反过来，这可以使用sum()简化：

SELECT (SUM(nes <> 0) +
        SUM(snes <> 0) +
        SUM(msx2 <> 0) +
        . . .
       ) as SumCount
FROM general_list
WHERE saga LIKE '%/FFI/%' ;

MySQL将布尔值视为整数，1为真。因此，使用SUM()计算匹配值的数量。

如何统一SQL COUNT

1 个答案: