[英]Mysql select distinct multiple columns loop through results
I'm trying to select categories without duplicates from 2 different columns, the table looks something like this: 我正在尝试从2个不同的列中选择没有重复的类别,表格看起来像这样:
cuisine_1 cuisine_2
----------------------
italian french
italian chinese
japanese german
western
french german
international
western sushi
sushi steak
steak
chinese
vietnamese chinese
Expected result is every category only once where it doesn't matter if it came from cuisine_1
or cuisine_2
预期结果是每个类别仅一次,无论它来自
cuisine_1
还是cuisine_2
I tried like so: 我试过像这样:
$categories=mysqli_query($link,"select distinct cuisine_1,cuisine_2 AS cuisine_unique from table");
while($row_cu=mysqli_fetch_array($categories)){
echo $row_cu['cuisine_unique']."<br>";
}
Without any luck so far. 到目前为止没有任何运气。 Do I have to group the results first, or what am I doing wrong ?
我必须首先对结果进行分组,还是我做错了什么?
问题是,如果您按cuisine_1
过滤, cuisine_1
丢失另一列的一些数据,因此您可以尝试通过为每一列获取一个SELECT DISTINCT
,然后合并两个数组并按array_unique
过滤
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