title: mysql Group by today
body: <p>Hello I would like to spend over mysql only all data with today's date. Unfortunately there is only GROUP BY YEAR and MONTH</p>
  
  <pre><code>SELECT rechnung.*, re_kunden.*,  SUM(re_kunden.gpreis) as preise 
  FROM rechnung
      LEFT JOIN re_kunden ON rechnung.ID = re_kunden.ID_rechnung
  WHERE rechnung.ID LIKE re_kunden.ID_rechnung
  GROUP BY ???TODAY???(rechnung.datum)
  </code></pre>
  
  <p>Data</p>
  
  <pre><code>+----+-------------+----------+------------+-------------+---------+
  | ID | rechnungsnr | kundennr |   datum    | lieferdatum | bezahlt |
  +----+-------------+----------+------------+-------------+---------+
  | 10 |       10010 |     1003 | 2018-12-09 | 2018-12-10  |       1 |
  | 11 |       10009 |     1005 | 2018-12-09 | 2018-12-10  |       1 |
  | 12 |       10011 |     1001 | 2018-12-10 | 2018-12-10  |       1 |
  | 13 |       10054 |     1004 | 2018-12-10 | 2018-12-10  |       1 |
  +----+-------------+----------+------------+-------------+---------+
  </code></pre>
  
  <p>and Data</p>
  
  <pre><code>+----+-------------+----------+-------------+-------+----------+--------+--------+------+
  | ID | ID_rechnung | position | bezeichnung | menge | einheit  | epreis | gpreis | text |
  +----+-------------+----------+-------------+-------+----------+--------+--------+------+
  |  1 |          10 |        1 | text        |     1 | text     |      1 |      1 | text |
  |  2 |          11 |        1 | text        |     2 | text     |      1 |      2 | text |
  |  3 |          12 |        1 | text        |     3 | text     |      1 |      3 | text |
  |  4 |          13 |        1 | text        |     1 | text     |      1 |      1 | text |
  +----+-------------+----------+-------------+-------+----------+--------+--------+------+
  </code></pre>
  
  <p></p>