SELECT CASE WHEN 用法

示例:

SELECT
    a.Sentence,
    b.Klg,
CASE
        b.字段1
        WHEN '1' THEN
        '正确' 
        else 
        '错误' end as 别名1,
    CASE
            b.字段2
            WHEN '1' THEN
            '可识别' 
            else
            '不可识别' end as 别名2
        FROM
            table1 a,
            table2 b
        WHERE
            a.SID = b.SID