業務場景說明：
假設待審覈的訂單表有三種狀態，分別是“正常待審覈”|“即將過期”|“已經過期”
訂單提交後10小時內未處理：正常待審覈
訂單提交後10-20小時之間未處理：即將過期
訂單提交後20小時後未處理：已經過期
表結構如圖：
數據準備：
要解決的問題：
校驗訂單表中不同狀態訂單的數量與前臺顯示是否一致
解決思路：
1、通過存儲過程，獲取數據庫中的不同時間段的待審覈訂單數量
2、將後臺獲取的數據與前臺進行比較
實現步驟如下：
=============================================================================
1、連接數據庫
mysql -uroot -hlocalhost -p123456 -P3306
=============================================================================
2、進入數據庫
use sqltestdb；
=============================================================================
3、創建存儲過程（直接複製到mysql命令行執行就可以了）：
DELIMITER //
CREATE PROCEDURE order_state(IN will_timeout int,IN already_timeout int)
BEGIN
declare count_normal int;
declare count_will int;
declare count_already int;
set @current_time=now();
set @time1=date_sub(@current_time, interval will_timeout hour);
select count(*) into count_normal from lijuan where order_time>@time1 and new_db=0;
select count_normal;
set @current_time=now();
set @time2=date_sub(@current_time, interval already_timeout hour);
select count(*) into count_will from lijuan where order_time>@time2 and new_db=0;
set count_will=count_will-count_normal;
select count_will;
select count(*) into count_already from lijuan where new_db=0;
set count_already=count_already-(count_will+count_normal);
select count_already;
END //
DELIMITER ;
==============================================================================
4、調用存儲過程
call order_state(10,20);
==============================================================================
5、刪除存儲過程
drop procedure order_state;
==============================================================================
存儲過程代碼解釋說明：
1-1聲明結束符爲“//”
DELIMITER //
1-2聲明存儲過程名稱及輸入參數的數量和類型：
存儲過程名稱：order_state
輸入參數的數量：2
IN:表示是入參
will_timeout:即將超時所用的時間（例：10小時）
already_timeout:已經超時所用的時間（例：20小時）
CREATE PROCEDURE order_state(IN will_timeout int,IN already_timeout int)
1-3表示開始
BEGIN
1-4聲明變量count_normal表示“正常”狀態的訂單的數量
declare count_normal int;
1-5聲明變量count_will表示“即將超時”狀態的訂單的數量
declare count_will int;
1-6聲明變量count_already表示“已經超時”狀態的訂單的數量
declare count_already int;
1-7獲取當前時間並賦值給變量@current_time
set @current_time=now();
1-8將當前時間減去“即將超時所用的時間”，然後再賦值給變量@time1
set @time1=date_sub(@current_time, interval will_timeout hour);
1-9查詢出“正常”狀態的訂單數量，並賦值給變量count_normal
select count(*) into count_normal from lijuan where order_time>@time1 and new_db=0;
1-10輸出“正常”狀態的訂單數量
select count_normal;
1-11將當前時間減去“已經超時所用的時間”，然後再賦值給變量@time2
set @time2=date_sub(@current_time, interval already_timeout hour);
1-12查詢出“正常”狀態+“即將超時”狀態的訂單數量之和，並賦值給變量count_will
select count(*) into count_will from lijuan where order_time>@time2 and new_db=0;
1-13將“正常”狀態+“即將超時”狀態的訂單數量之和（即count_will）減去“正常”狀態的訂單數量（即count_normal）,然後再賦值給count_will
set count_will=count_will-count_normal;
1-14輸出“即將超時”狀態的訂單數量
select count_will;
1-15查詢出所有狀態的訂單數量（通過new_db=0過濾舊數據庫的數據）
select count(*) into count_invalid from lijuan where new_db=0;
1-16將所有訂單的數量減去“正常”狀態+“即將超時”狀態的訂單數量之和(即count_will+count_normal)
set count_invalid=count_already-(count_will+count_normal);
1-17輸出“已經超時”狀態的訂單數量
select count_already;
1-18結束
END //
1-19將結束符修改爲“;”
DELIMITER ;
**********書山有路，學海無涯，無數個孤獨的夜晚，需要一點小小的成就感！**********