我想了解是否有更有效的方法来编写以下查询：
SELECT *
FROM requests srp
INNER JOIN surgeons rpsur
ON rpsur.id = srp.surgeon_id
LEFT OUTER JOIN #usersurgeons usersurgeons
ON usersurgeons.surgeon_id = srp.surgeon_id
LEFT OUTER JOIN surgeons LOsurgeons
ON usersurgeons.surgeon_id = LOsurgeons.id
LEFT OUTER JOIN provsurgeons LOprovsurgeons
ON LOprovsurgeons.id = LOsurgeons.provsurgeon_id
INNER JOIN #selectedsurgeons up
ON up.surgeon_id = rpsur.id
LEFT OUTER JOIN provsurgeons ps
ON ps.id = rpsur.provsurgeon_id
WHERE rpsur.isprimary = 0
AND usersurgeons.isprimary = 0
AND LOsurgeons.isprimary = 0
AND LOprovsurgeons.isprimary = 0
AND up.isprimary = 0
AND ps.isprimary = 0
我对这里的where子句不满意，是否有更专业的方式来编写它，而不是将子句添加到连接行（例如on xx.id = yy.id and xx.isPrimary=0）??
答案 0 :(得分：2)
仅从这个查询来看，可以说的事情并不多。您应该考虑添加更多上下文（如何将数据导入这些临时表和％外科医生表的结构）：
1）Select *几乎不可能使用任何索引，并在最终结果中提供了很多列（Requests.*，surgeons.*，Provsurgeons.*等。只返回您需要的列。
2）如果在您的查询中经常执行isPrimary = 0过滤（不仅仅是这个过滤），您可以考虑创建一个视图来获取由isPrimary = 0过滤的数据。 vwSurgeons，vwProvsurgeons。然后，您可以直接加入视图而不是表格。
3）[已在评论中提及]任何排除NULL ed表的OUTER JOIN值的条件都会将OUTER转换为INNER。
答案 1 :(得分：0)
不使用连接所有表并在末尾使用where子句，而是仅使用带有筛选记录的派生表。这样您的查询性能会更好。
SELECT *
FROM requests srp
INNER JOIN surgeons rpsur
ON rpsur.id = srp.surgeon_id
LEFT OUTER JOIN
(
SELECT *
FROM #usersurgeons
WHERE isprimary = 0
)usersurgeons
ON usersurgeons.surgeon_id = srp.surgeon_id
LEFT OUTER JOIN
(
SELECT *
FROM surgeons
WHERE isprimary = 0
)LOsurgeons
ON usersurgeons.surgeon_id = LOsurgeons.id
LEFT OUTER JOIN
(
SELECT *
FROM provsurgeons
WHERE isprimary = 0
)LOprovsurgeons
ON LOprovsurgeons.id = LOsurgeons.provsurgeon_id
INNER JOIN
(
SELECT *
FROM #selectedsurgeons
WHERE isprimary = 0
)up
ON up.surgeon_id = rpsur.id
LEFT OUTER JOIN
(
SELECT *
FROM provsurgeons
WHERE isprimary = 0
) ps
ON ps.id = rpsur.provsurgeon_id
WHERE rpsur.isprimary = 0