獲取多個條件的計數

Question

我的問題是我想在單個查詢中獲得三個條件的計數。我知道我可以運行多個查詢做到這一點，但問題是我需要它在一個查詢

我查詢我曾嘗試是

SELECT COUNT(IF(da <3, da, 0)) AS da1, 
     COUNT(IF(da <2, da, 0)) AS da2, 
     COUNT(IF(da <1, da, 0)) AS da3 
FROM tv 

而其結果是

4 4 4 

但預期結果是

2 1 0 

表內數據存在da列是需要

3 2 1 3 

Answer 1

SELECT SUM(IF(rr <3, 1, 0)) AS da1, 
     SUM(IF(rr <2, 1, 0)) AS da2, 
     SUM(IF(rr <1, 1, 0)) AS da3 
FROM tv; 

Answer 2

COUNT()與GROUP BY使用 - 我認爲這可能是你的問題，試圖通過`da`分組。

Answer 3

我才發現我的問題，但PSR的解決方案的解決方案也是正確

SELECT * 
FROM (

    SELECT COUNT(da) AS da1 
    FROM tv 
    WHERE da <3 
    ) AS da1, (

    SELECT COUNT(da) AS da2 
    FROM tv 
    WHERE da <2 
    ) AS da2, (

    SELECT COUNT(da) AS da3 
    FROM tv 
    WHERE da <1 
    ) AS da3