[英]Joining a derived table postgres
我有4張桌子:
現在,我正在嘗試編寫此查詢以計算總數,並吐出能力,id和用戶是否已達到限制。 一切正常,除了我添加用戶時。 我不確定自己在做什么錯,一旦我在where子句中限制了用戶的呼叫能力,我就會得到一個很小的子集,該子集僅存在於我想要整個能力列表時返回的call_competency中。
沒有達到的能力應該是錯誤的,記錄的正確數字應該是正確的。 能力表中的完整列表。
我添加了派生表,不確定這是否正確,顯然它不能正常運行,不確定我在做什么錯,我在浪費時間。 任何幫助,不勝感激。
SELECT comp.id, comp.shortname, comp.description,
CASE WHEN sum(CASE WHEN crs.grade = 'Pass' THEN 1 ELSE CASE WHEN crs.grade = 'Fail' THEN -1 ELSE 0 END END) >= comp_l.competency_break_level
THEN TRUE ELSE FALSE END
FROM competencies comp
INNER JOIN competency_levels comp_l ON comp_l.competency_group = comp.competency_group
LEFT OUTER JOIN (
SELECT competency_id
FROM call_competency
WHERE call_competency.user_id IN (
SELECT users.id FROM users WHERE email= _studentemail
)
) call_c ON call_c.competency_id = comp.id
LEFT OUTER JOIN competency_review_status crs ON crs.id = call_competency.review_status_id
GROUP BY comp.id, comp.shortname, comp.description, comp_l.competency_break_level
ORDER BY comp.id;
(從臀部射擊,無需安裝即可測試)
看起來下面應該可以解決問題。 您顯然混合了一些連接,其中有一個未引用的關系列。 同樣,主查詢中的CASE
語句可能更簡潔。
SELECT comp.id, comp.shortname, comp.description,
(sum(CASE WHEN crs.grade = 'Pass' THEN 1 WHEN crs.grade = 'Fail' THEN -1 ELSE 0 END) >= comp_l.competency_break_level) AS reached_limit
FROM competencies comp
JOIN competency_levels comp_l USING (competency_group)
LEFT JOIN (
SELECT competency_id, review_status_id
FROM call_competency
JOIN users ON id = user_id
WHERE email = _studentemail
) call_c ON call_c.competency_id = comp.id
LEFT JOIN competency_review_status crs ON crs.id = call_c.review_status_id
GROUP BY comp.id, comp.shortname, comp.description
ORDER BY comp.id;
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