Question

我需要根据3个条件过滤SQL查询结果：
1.位置
2.医生姓名
3.专业名称

如果所有3个条件都不为空，则下面是sql查询：

if (location != "" && doctor!="" && specialty!="")

select Location, ...
from clinicdoctors
where Location = @Location and DoctorName = @DoctorName and SpecialtyName = @SpecialtyName

}

如果只有位置为空，

if (location == "" && doctor!="" && specialty!="")
select Location, ...
from clinicdoctors
where Location is not null and DoctorName = @DoctorName and SpecialtyName = @SpecialtyName

...

如果我想检查所有条件，我需要写8个if语句。在这种情况下，我该怎么做才能简化代码？

Answer 1

select Location, ...
from clinicdoctors
where 
 ISNULL(@Location,Location) = Location
 and ISNULL(@DoctorName,DoctorName) = DoctorName
 and ISNULL(@SpecialtyName,SpecialtyName) = SpecialtyName

Answer 2

我认为在代码中执行此操作比使用sql更好。由于查询是如此不同，所以没有任何解决方法，但简单的方法是：

$loc_where = empty($loc) ? 'Location IS NOT NULL' : "Location = $loc";
$doc_where = empty($doc) ? 'AND DoctorName IS NOT NULL' : "AND DoctorName = $doc";
$spec_where = empty($spec) ? 'AND SpecialtyName IS NOT NULL' : "AND SpecialtyName = $spec";

query ... WHERE $loc_where $doc_where $spec_where

SQL语句过滤结果

2 个答案: