Question

我正在执行一个mysql查询。我正在加入4桌。我希望只有当p.location_id不等于0时才会将两条粗线连接到查询中。我希望它们在p.location_id等于0时不会被执行

SELECT p. * 
FROM property p, property_type pt, location l, city c
WHERE p.status =1
AND (
pt.prop_name LIKE  '%dlf%'
OR p.furnish LIKE  '%dlf%'
OR p.description LIKE  '%dlf%'
OR p.bed LIKE  '%dlf%'
OR p.term_condition LIKE  '%dlf%'
OR p.bedroom LIKE  '%dlf%'
OR p.property_type LIKE  '%dlf%'
OR c.city_name LIKE  '%dlf%'
**OR l.loct_name LIKE  '%dlf%'**
)
AND p.prop_id = pt.prop_id
AND p.city = c.city_id
**AND p.location_id = l.loct_id**
ORDER BY sortnum

我有什么方法可以实现这一目标。

Answer 1

将查询保存在字符串中，并根据执行前的条件将字符串连接起来....

伪代码是

sql = "the query";

if(condition)
{
sql.="what you want to add"
}

编辑：试试这个 SELECT p。 * ......... IF（p.location_id！= 0，AND p.location_id = l.loct_id，NULL）ORDER BY sortnum 编辑2：

SELECT p. * FROM property p, property_type pt, location l, city c WHERE p.status =1 AND (pt.prop_name LIKE '%dlf%' OR p.furnish LIKE '%dlf%' OR p.description LIKE '%dlf%' OR p.bed LIKE '%dlf%' OR p.term_condition LIKE '%dlf%' OR p.bedroom LIKE '%dlf%' OR p.property_type LIKE '%dlf%' OR p.property_type LIKE '%dlf%' OR c.city_name LIKE '%dlf%' OR (IF(p.location_id !=0 , l.loct_name LIKE '%dlf%',NULL))) AND p.prop_id = pt.prop_id AND p.city = c.city_id AND (IF(p.location_id != 0),p.location_id = l.loct_id,NULL) ORDER BY shortnum

Answer 2

SELECT p.* 
FROM property p, property_type pt, location l, city c
WHERE p.status =1
AND (
    pt.prop_name LIKE  '%dlf%'
    OR p.furnish LIKE  '%dlf%'
    OR p.description LIKE  '%dlf%'
    OR p.bed LIKE  '%dlf%'
    OR p.term_condition LIKE  '%dlf%'
    OR p.bedroom LIKE  '%dlf%'
    OR p.property_type LIKE  '%dlf%'
    OR c.city_name LIKE  '%dlf%'
    OR (p.location_id <> 0 AND l.loct_name LIKE  '%dlf%')
)
AND p.prop_id = pt.prop_id
AND p.city = c.city_id
AND (p.location_id = 0 OR p.location_id = l.loct_id)
ORDER BY sortnum

您只需要更多逻辑条件。代码仍然存在，但是当你想要的条件发生时SQL不会运行它。

执行时动态删除部分sql查询

2 个答案: