Question

此MySQL查询具有联合和规范化功能，我不知道如何编写laravel查询。

SELECT DISTINCT val
FROM
(
    SELECT 'date' date_type, date val FROM user_presentation
    UNION
    SELECT 'accept_date', accept_date FROM user_presentation
    UNION
    SELECT 'question_date', question_date FROM user_presentation
    UNION
    SELECT 'success_date', success_date FROM user_presentation
) normalized;

Answer 1

您可以在Laravel代码中链接一系列联合：

$first = DB::table('user_presentation')
    ->select('date');

$second = DB::table('user_presentation')
    ->select('accept_date');

$third = DB::table('user_presentation')
    ->select('question_date');

$fourth = DB::table('user_presentation')
    ->select('success_date AS val')
    ->union($first)
    ->union($second)
    ->union($third)
    ->get();

请注意，上面的代码实际上与此查询相对应：

SELECT date AS val FROM user_presentation UNION
SELECT accept_date FROM user_presentation UNION
SELECT question_date FROM user_presentation UNION
SELECT success_date FROM user_presentation;

此外，您不必使用DISTINCT子查询，因为联合查询本身应删除所有重复的日期值。

Answer 2

$userP = UserPresentation::get()
->only('date', 'accept_date', 'question_date', 'success_date')
->unique();

使用Collection的100％Laravel方式，这将一起选择所有四个日期，Laravel Collection将从这些选择中找到唯一的行。

MySQL联合查询到laravel查询

2 个答案: