mySql變量應用示例

-- 1.自定義一個時間變量並設置爲當前日期的前一天
SET @startTime = CONCAT(date_sub(curdate(),interval 1 day),'%');
-- 也能夠從這裏手動指定日期
-- SET @startTime = '2017-04-13%';
-- 顯示要查詢的日期
-- select  @startTime;
select REPLACE(@startTime,'%','') as 日期,當日活躍用戶,當日新增用戶 from
(
        -- 2.查詢當日活躍用戶
        select '01' as id,count(1) as 當日活躍用戶 from (
                select DISTINCT uname from app_loginLog where logindate like @startTime
        ) as t
) as a,
 -- 3.查詢當日新增用戶
(select '01' as id,count(1) as 當日新增用戶 from app_user where registerdate like @startTime) b
where a.id = b.id;