將兩個計數查詢合並為一個

Question

我有兩個問題

SELECT course,
COUNT(*) AS countp 
FROM table1 
WHERE pickout='Yes' 
GROUP BY course

SELECT course,
COUNT(*) AS countw
FROM table1
WHERE pickout='Yes' AND result='Won'
GROUP BY course

我想要實現的是一個具有三列Course ， Countp ， Countw的表，但是我很難將兩者合並為一個查詢。

基本上，我正在尋找選秀次數和獲勝次數的課程列表。

Answer 1

在MySQL中，條件的結果評估為1或0 。 你可以總結一下

SELECT course, 
       sum(pickout='Yes') AS countp,
       sum(pickout='Yes' AND result='Won') AS countw
FROM table1 
GROUP BY course

Answer 2

嘗試以下SQL：

SELECT 
Course,
COUNT(*) AS CountP,
SUM(CASE WHEN result='Won' THEN 1 ELSE 0 END) AS CountW
FROM table1
WHERE pickout = 'Yes'
GROUP BY Course

Answer 3

嘗試這個：

select a.course,a.countp ,b.countw  from (SELECT course, COUNT(*) AS countp FROM table1 WHERE pickout='Yes' GROUP BY course)a full join 
(SELECT course, COUNT(*) AS countw FROM table1 WHERE pickout='Yes' AND result='Won' GROUP BY course)b
a.course=b.course