下面的 SQL 查询对我有用,但是当 staffNo 为空 6 次(每个工作人员一次)时,它返回属性值。即使 staffNo 为空,我也想归还财产所有者,没有 6 个回报。
SELECT s.branchNo, s.staffNo, s.fName, s.lName, propertyNo, p.staffNo,
o.fName, o.lName, o.ownerNo
FROM staff s, propertyforrent p, privateowner o
WHERE s.staffNo = p.staffNo AND o.ownerNo = p.ownerNo
OR p.staffNo IS NULL AND o.ownerNo = p.ownerNo
ORDER BY s.branchNo, s.staffNo, propertyNo
结果
B003 SG14 David Ford PG16 SG14 Tony Shaw CO93
B003 SG14 David Ford PG4 NULL Tina Murphy CO40
B003 SG37 Ann Beech PG21 SG37 Carol Farrel CO87
B003 SG37 Ann Beech PG36 SG37 Tony Shaw CO93
B003 SG37 Ann Beech PG4 NULL Tina Murphy CO40
B003 SG5 Susan Brand PG4 NULL Tina Murphy CO40
B005 SL21 John White PG4 NULL Tina Murphy CO40
B005 SL41 Julie Lee PG4 NULL Tina Murphy CO40
B005 SL41 Julie Lee PL94 SL41 Carol Farrel CO87
B007 SA9 Mary Howe PA14 SA9 Joe Keogh CO46
B007 SA9 Mary Howe PG4 NULL Tina Murphy CO40
这是想要的结果
B003 SG14 David Ford PG16 SG14 Tony Shaw CO93
B003 SG14 PG4 NULL Tina Murphy CO40
B003 SG37 Ann Beech PG21 SG37 Carol Farrel CO87
B003 SG37 Ann Beech PG36 SG37 Tony Shaw CO93
B005 SL41 Julie Lee PL94 SL41 Carol Farrel CO87
B007 SA9 Mary Howe PA14 SA9 Joe Keogh CO46
提前致谢!