显示列的sql查询输出 [英] display sql query output for columns
本文介绍了显示列的sql查询输出的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我有这张桌子
id | apple | banana | coconut | pear|
1 1 1 1 0
2 0 0 1 1
3 1 0 0 1
和此sql查询
select tree
from ((select id, 'apple' as tree
from trees
where apple = 1
) union all
(select id, 'banana' as tree
from trees
where banana = 1
) union all
(select id, 'coconut' as tree
from trees
where coconut = 1
) union all
(select id, 'pear' as tree
from trees
where pear = 1
)
) t
where id = 1;
输出是
apple
banana
coconut
我该如何用php写这个,以便我可以回显结果
how would i write this in php so i can echo out the result
这是我到目前为止所拥有的
this is what i have so far
$sql = " select tree
from ((select id, 'apple' as tree
from trees
where apple = 1
) union all
(select id, 'banana' as tree
from trees
where banana = 1
) union all
(select id, 'coconut' as tree
from trees
where coconut = 1
) union all
(select id, 'pear' as tree
from trees
where pear = 1
)
) t
where id = '$id'";
$result = mysqli_query($conn, $sql);
但是我不知道该怎么办之后,我无法进行while循环,或者只是回显它给出错误的结果
but i dont know what to do after this i cant put a while loop or just echo out the result it gives an error
推荐答案
您可以简单地使用mysqli_fetch_assoc()
循环搜索结果:
You can simply loop over your results using mysqli_fetch_assoc()
:
while ($row = mysqli_fetch_assoc($result)) {
echo $row['tree'] . "\n";
}
但是,执行类似的操作可能更简单/有效,该操作使用列名称生成输出数据,并在列的值不为0时回显该名称:
However, it is probably simpler/more efficient to do something like this, which uses the column names to generate the output data, echoing the name when the value in the column is not 0:
$sql = "SELECT * FROM trees WHERE id = '$id'";
$result = mysqli_query($conn, $sql);
while ($row = mysqli_fetch_assoc($result)) {
foreach ($row as $key => $value) {
if ($key == 'id') continue;
if ($value) echo "$key\n";
}
}
这篇关于显示列的sql查询输出的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
查看全文