【SQL】if else

基本

PHP

   if ($score >= 90)
     $str = 'A';
    elseif ($score >= 70 && $score < 90) 
     $str = 'B';
    elseif ($score >= 60 && $score < 70) 
     $str = 'C';  
    else{
     $str = 'D';  
    }
     
  

SQL

   CASE  
     WHEN score >= 90 THEN 'A'
      WHEN score >= 90 THEN 'B'
      WHEN score >= 90 THEN 'C'
      ELSE 'D'
    END AS str
  

欄位值

Name	Answer
張一	1
王二	2
李三	3

    SELECT Name, 
     case Answer
       when 1 then '喜歡'
       when 2 then '不喜歡'
       when 3 then '一般'
      END
    FROM table;
    
    OR
    
    SELECT Name, 
     case
       when Answer=1 then '喜歡'
       when Answer=2 then '不喜歡'
       when Answer=3 then '一般'
      END AS Answer
      FROM table;