我有3个表,位置,查找并排除以下信息...
位置表
+----+--------------+
| id | location |
+----+--------------+
| 1 | Location a |
| 2 | Location b |
| 3 | Location c |
| 5 | Location d |
| 6 | Location e |
| 7 | Location f |
| 8 | Location g |
| 9 | Location h |
+----+--------------+
查找表
+----+-------------+------+
| id | location_id | code |
+----+-------------+------+
| 1 | 2 | PR6 |
| 2 | 2 | PR7 |
| 3 | 2 | PR9 |
| 4 | 5 | WA2 |
| 6 | 8 | WA3 |
+----+-------------+------+
排除表
+----+-------------+------+
| id | location_id | code |
+----+-------------+------+
| 1 | 2 | PR5 |
| 2 | 2 | PR8 |
+----+-------------+------+
这些表用于基本的邮政编码查找。我需要创建一些SQL,以便可以使用邮政编码进行搜索,但是我需要考虑所有排除的邮政编码,例如...如果我要搜索“ PR7”,我将得到“位置B”但是如果我要搜索PR5或PR8,我将不会获得“位置B”,因为这些在排除表中。这是我到目前为止所拥有的...
SELECT
lookup.*, exclude.`code` as exclude, location.location
FROM lookup
LEFT JOIN
exclude
ON lookup.location_id = exclude.location_id
LEFT JOIN
location
ON location.location = lookup.location_id
WHERE lookup.`code` LIKE 'PR%' AND (exclude.`code` NOT LIKE 'PR8%' OR ISNULL(exclude.`code`))
GROUP BY location.location
ORDER BY location.id
在上面的SQL中,用户键入了“ PR8”,该正使用PHP变量发送到where子句,我在查找表中查找邮政编码的前2个字母,然后我还要尝试查找用户输入的内容在排除表中将其从结果中忽略。不幸的是,我不能说出我要去哪里,我得到以下结果,根据上表,由于排除,我应该没有结果...
+----+-------------+------+---------+
| id | location | code | exclude |
+----+-------------+------+---------+
| 1 | Location b | PR8 | PR5 |
+----+-------------+------+---------+
我希望我已经解释得足够好了,但是请告诉我是否需要添加更多细节。
非常感谢您提供一些指导,在此先感谢:)
最佳答案
我认为您使用“ NOT IN”。
因此,您的“ AND”将更像
AND lookup.`code` NOT IN (SELECT 'code' FROM exclude)
编辑
我很确定这是可行的,不确定最佳性能,我会将其留给比我聪明的人。
SELECT
lookup.*, location.location
FROM lookup
LEFT JOIN
location
ON location.id = lookup.location_id
WHERE lookup.`code` LIKE 'PR%'
AND lookup.`code` NOT IN (SELECT `code` FROM exclude)
GROUP BY location.location
ORDER BY location.id
关于php - MySQL查询加入3个表,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/18405352/