Question

我有一个数据库表（大约10000多行），上面有这样的数据。

tags_id   tag_name  contact   date_applied
   1        happy     12         2019-04-01
   2        sad       67         2019-04-01
   1        happy     96         2019-04-01
   3        angry     56         2019-04-02
   2        happy     43         2019-04-02

现在我需要这张桌子看起来像这样。

date_applied  happy  sad  angry
 2019-04-01     2     1     0
 2019-04-02     1     0     1

如何在Laravel / PHP中实现这一目标？我需要将其保存到另一个数据库表或文件中。

Answer 1

尝试以下查询。

DB::table('table_name')
->select(DB::raw("
    sum( case when tag_name = 'happy' then 1 else 0 end) as happy
    ,sum( case when tag_name = 'sad' then 1 else 0 end) as sad
    ,sum( case when tag_name = 'angry' then 1 else 0 end) as angry
"), 'date_applied')
->groupBy('date_applied');

或者您可以使用直接查询

select date_applied
,sum( case when tag_name = 'happy' then 1 else 0 end) as happy
,sum( case when tag_name = 'sad' then 1 else 0 end) as sad
,sum( case when tag_name = 'angry' then 1 else 0 end) as angry
from table
group by date_applied

对于动态代码，

$tags = Tag::all();
$selectQuery = '';
foreach($tags as $tag){
    $selectQuery.="sum( case when tag_name = '".$tag->tag_name."' then 1 else 0 end) as ".$tag->tag_name.",";
}

DB::table('table_name')
->select(DB::raw($selectQuery."date_applied")
->groupBy('date_applied')

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