使用左联接返回两个查询/表中的所有行

Question

I have two subqueries on which I am doing a join, first one returns following data:

array (size=110)
  0 => 
    array (size=3)
      'scans' => string '7' (length=1)
      'bonus_points' => string '0' (length=1)
      'date' => string '2017-06-13' (length=10)
  1 => 
    array (size=3)
      'scans' => string '20' (length=2)
      'bonus_points' => string '0' (length=1)
      'date' => string '2017-06-14' (length=10)

second one:

array (size=21)
  0 => 
    array (size=2)
      'redeems' => string '1' (length=1)
      'date' => string '2017-06-14' (length=10)

If I do a left join on those two like so:

LEFT JOIN query2 ON query2.date=query1.date;

I get the following:

array (size=110)
  0 => 
    array (size=4)
      'scans' => string '7' (length=1)
      'bonus_points' => string '0' (length=1)
      'date' => null
      'redeems' => null
  1 => 
    array (size=4)
      'scans' => string '20' (length=2)
      'bonus_points' => string '0' (length=1)
      'date' => string '2017-06-14' (length=10)
      'redeems' => string '1' (length=1)

Everything is as I want it to be, except that the left query doesn't always have the same dates as the right query and then the result is 'date' => null .

How can I keep the data from both queries?

Answer 1

从左侧表中选择date列，而不是从右侧（连接）中选择date列。