我有以下有效的查询,但我想知道它是否可以更有效。我需要电话簿表 (pb) 中 4 名员工的名字和姓氏,他们的徽章(员工 ID)存储在 promise 表中
SELECT Originator_ID,
(SELECT pb.lname FROM pb WHERE pb.badge = Commitment.Originator_ID) AS Originator_Last_Name,
(SELECT pb.fname FROM pb WHERE pb.badge = Commitment.Originator_ID) AS Originator_First_Name,
Checker_ID,
(SELECT pb.lname FROM pb WHERE pb.badge = Commitment.Checker_ID) AS Checker_Last_Name,
(SELECT pb.fname FROM pb WHERE pb.badge = Commitment.Checker_ID) AS Checker_First_Name,
Reviewer_ID,
(SELECT pb.lname FROM pb WHERE pb.badge = Commitment.Reviewer_ID) AS Reviewer_Last_Name,
(SELECT pb.fname FROM pb WHERE pb.badge = Commitment.Reviewer_ID) AS Reviewer_First_Name,
Approver_ID,
(SELECT pb.lname FROM pb WHERE pb.badge = Commitment.Approver_ID) AS Approver_Last_Name,
(SELECT pb.fname FROM pb WHERE pb.badge = Commitment.Approver_ID) AS Approver_First_Name
FROM Commitment
WHERE Commitment.Approver_ID IN (SELECT pb.badge FROM pb WHERE pb.dept = ?) ORDER BY Commitment_ID
我的查询是否有太多子查询?
或者我应该将 4 个员工徽章标准化并分成一个单独的表吗?如果我要标准化,似乎我存储徽章的新表需要某种角色列,然后我是否需要该角色的第三个查找表?然后,让事情变得复杂的是,我需要使用传入的绑定(bind)变量“dept”按 Approver_ID 查询 promise 。不知道该走哪条路。
TABLE: commitment_emp
Commitment_ID (PK) (FK) VARCHAR2(10)
badge (PK) VARCHAR2(10)
role (PK) VARCHAR2(20)
最佳答案
用途:
SELECT c.originator_id,
orig.lname,
orig.fname,
c.checker_id,
check.lname,
check.fname,
c.reviewer_id,
review.lname,
review.fname,
c.approver_id,
approve.lname,
approve.fname
FROM COMMITMENT c
LEFT JOIN PB orig ON orig.badge = c.originator_id
LEFT JOIN PB check ON check.badge = c.checker_id
LEFT JOIN PB review ON review.badge = c.reviewer_id
JOIN PB approve ON approve.badge = c.approver_id
AND approve.dept ?
ORDER BY c.commitment_id
JOIN 和表别名是您的 friend - 表设计很好。
关于sql - Oracle sql 查询带有子查询还是应该规范化?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/3366847/