MySQL更改標簽值選擇不同並計數

Question

我有以下查詢：

SELECT DISTINCT GRAD_ACAD,
COUNT(GRAD_ACAD) AS subtotal
FROM academicos
WHERE CCN REGEXP 'I|D65'
GROUP BY GRAD_ACAD
ORDER BY GRAD_ACAD

結果是：

GRAD_ACAD  subtotal
DOC          11
LIC           2
MTR           3

我要做的是將值標簽更改為以下內容：

GRAD_ACAD      subtotal
Doctorado        11
Licenciatura      2
Maestría          3

我已經嘗試過Case了，但是卻無法正常工作：

SELECT DISTINCT GRAD_ACAD CASE GRAD_ACAD WHEN 'DOC' THEN 'doctorado' ELSE(SELECT GRAD_ACAD) END AS GRAD_ACAD,
COUNT(GRAD_ACAD) AS subtotal
FROM academicos
WHERE CCN REGEXP 'I|D65'
GROUP BY GRAD_ACAD
ORDER BY GRAD_ACAD

我怎樣才能解決這個問題？

Answer 1

case GRAD_ACAD when 'DOC' then 'Doctorado' when 'LIC' then 'Licenciatura' when 'MTR' then 'Maestria' else GRAD_ACAD end

您需要在SELECT和GROUP BY中都放入相同的子句

Answer 2

無需在此處使用DISTINCT

SELECT  CASE GRAD_ACAD WHEN 'DOC' THEN 'doctorado' 
                 WHEN 'LIC' then 'Licenciatura'
                 WHEN 'MTR' then 'Maestria'
                 ELSE GRAD_ACAD end,
COUNT(GRAD_ACAD) AS subtotal
FROM academicos
WHERE CCN REGEXP 'I|D65'
GROUP BY 1
ORDER BY 1;

注意，我使用了group by 1和order by 1來指定第一個選定字段，而不是在兩個子句中都重復這種情況。