mysql - mysql查询中的CASE函数

Question

我无法从以下查询中获得我想要的结果。我可以得到一点帮助吗？谢谢。

$sql = "SELECT id, 
                 CASE 
                    when Rcon = '' then '0',
                    when Rcon = 'x' then '1',
                    when Rcon = '2x' then '2',
                    when Rcon = 'x3' then '2',
                    when Rcon = 'x,x3' then '3',
                    when Rcon = 'x4' then '3' 
                    ELSE Rcon END AS Rcon
FROM mytable";

Answer 1

您的 CASE 语句有问题。

SELECT  id, 
        CASE 
          when Rcon = '' then '0'
          when Rcon = 'x' then '1'
          when Rcon = '2x' then '2'
          when Rcon = 'x3' then '2'
          when Rcon = 'x,x3' then '3'
          when Rcon = 'x4' then '3' 
          ELSE Rcon 
        END AS Rcon
  FROM mytable;

请注意，我已从 CASE 语句的每行末尾删除了逗号 (,)。逗号在 case 语句中无效。