sql-case when else 字符转对应内容

-- 相当于Java的switch

SELECT DISTINCT
        a.id,
        (case
            when a.ticket_id is not null then '是'
            else '否'
        end
        ) is_use_ticket,
        a.create_time,
        (CASE b.authentication
            WHEN 1 THEN '未认证'
            WHEN 2 THEN '已认证'
            WHEN 3 THEN '待审核'
            WHEN 4 THEN '认证失败'
            ELSE '其他'
        END) authentication
        FROM abcd AS a LEFT JOIN dcba AS b ON a.id = b.aid;