搜索別名的正確方法是什么？在下面的代碼中，我創建了一個名為 (USER) 的別名，在此列中，我收集了 (DE) 和 (PARA) 列中的所有值。(SELECT *, de as user FROM mensagens WHERE user = '1' GROUP BY projeto ORDER BY data DESC) UNION(SELECT *, para as user FROM mensagens WHERE user = '1' GROUP BY projeto ORDER BY data DESC)SQL在線：http ://sqlfiddle.com/#!9/d506b7/2
1 回答
呼如林
TA貢獻1798條經驗 獲得超3個贊
你可以做
select * from
(
SELECT *, de as user FROM mensagens
UNION
SELECT *, para FROM mensagens
) tmp
where user = 1
GROUP BY projeto
ORDER BY data DESC
或者更簡單：
SELECT *
FROM mensagens
WHERE 1 in (de, para)
GROUP BY projeto
ORDER BY data DESC
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