数据库查询以使用user_id选择最大行

Question

我需要从表中选择user_id

的最大数据库条目行

表名：cd_production

code_cd  etaireia  etos
______________________
400400  ODEON     1987
400401  ODEON     1986
400412  COLUMBIA  1990
400420  COLUMBIA  1990
400657  LYRA      1965
410000  COLUMBIA  1962
410001  COLUMBIA  1964
410003  PHILIPS   1979
410005  PHILIPS   1971
420430  ODEON     2002
420440  LYRA      2005
420450  COLUMBIA  2009
420460  ODEON     2007
420470  PHILIPS   2008
420480  ODEON     2002
420490  COLUMBIA  2010
500500  SONY      1968
500510  SONY      1972
600601  COLUMBIA  1962
600602  COLUMBIA  1963
600603  ODEON     1964
670670  PHILIPS   1983
asad

Answer 1

你应该尝试这样的事情

    $result=this->db->query("select max(user_id) as maxValue form tableName")->result_array();
    $maxValue=$result[0]['maxValue']; //or $result['maxValue']; 
    echo $maxValue;
  $result2=this->db->query("select * from tableName user user_id=$maxValue")->result_array();

var_dump($result2);