Question

php多条件查询

我有一个student 表其中表中有字段name ,age,sex, nation,deep,mobile,telephone,
但我的查询条件去时name，sex，deep，我查询的条件3个中任意一个或多个可以为空值
我要才结果却是name, mobile,nation.我想请教的重点是任意一个值为空或多个值为空怎么写，小弟我很纠结。。请用php些出来我给50分。。

Answer 1

$sql = "SELECT * FROM user WHERE name LIKE '%".$name."%' AND age LIKE '%".$age."%' AND sex LIKE '%".$sex."%' ORDER BY id ASC

仔细看看吧 相信你能看懂的。
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楼主..模糊查询的条件为空的时候是完全匹配的。
$sql = "SELECT * FROM user WHERE name LIKE '%%' AND age LIKE '%%' AND sex LIKE '%%' ORDER BY id ASC
下面这样子才是空值 搜不到任何东西的。
$sql = "SELECT * FROM user WHERE name LIKE '% %' AND age LIKE '% %' AND sex LIKE '% %' ORDER BY id ASC
你再仔细看看 区别 多试试...我用这么久还没见过他不好使呢。。

Answer 2

$sql = "SELECT name,mobile,nation FROM student WHERE name="null" or sex="null" or deep="null";

Answer 3

<?
$sql = "select * from student where 1";
if($name) {
$sql .= " and name = '$name'"
}

if($sex) {
$sql .= " and sex = '$sex'"
}

if($deep) {
$sql .= " and deep = '$deep'"
}
?>