1. 獲取指定日期幾天後的日期
SELECT SUM(give_num-have_used_num)
FROM a
WHERE customer_id=#{myCustomerId}
AND (date_add(create_date, interval enable_days_num day) >= CURRENT_DATE() OR enable_type=3)
2. 判斷字段值,進行替換,最後as別名,實體類接收
CASE
WHEN t.task_status = '1' THEN '已完成'
WHEN t.task_status = '2' THEN '未完成'
END AS task_status
3. 聯表查詢,取其他表字段值,拼接,最後as別名,實體類接收
CONCAT(u.nick_name,'[',p.POSITION_NAME,']') AS name