SQL Server 游标的使用示例

Ø  简介

本文主要记录 MSSQL 中的游标使用示例，在有必要时方便借鉴查阅。游标一般定义在某段功能性的 SQL 语句中，或者存储过程中。之所以选择用它，是因为有时候无法使用简单的 SQL 语句满足我们需求，比如需要对结果集中的每一条数据，根据不同条件进行不同操作（CRUD），这时我们就可以使用游标来完成。

提示：来之 DBA 的杰作，哈哈~~

1.   示例1：

本示例，用于初始化某新表的数据。使用游标遍历查询结果集，根据遍历的数据再插入另外两张表。SQL 代码如下：

IF(OBJECT_ID('SP_Init_CustomerNewOpening', ：

1)   本示例，创建了一个存储过程，创建了两个游标。

2)   第一个游标，使用游标完成更新遍历的记录，再使用遍历的数据完成对另外两张表的 Insert 操作。

3)   第二个游标，完成对3张表的更新操作，在示例中使用了当前游标记录作为更新条件，例如：WHERE CURRENT OF cursor_Crm_Refundment。

4)   该存储过程用于定时任务执行，比在程序中去查询数据，然后再遍历写入数据效率上还是比较有优势的，而且便于维护。SQL 代码如下：

IF(OBJECT_ID('SP_Add_CustomerNewOpening', 'P') IS NOT NULL)

DROP PROCEDURE SP_Add_CustomerNewOpening;

GO

CREATE PROCEDURE SP_Add_CustomerNewOpening

(

@StartTime datetime,                --开始时间

@EndTime datetime                   --结束时间

)

AS

DECLARE @Remark varchar(8000) = NULL;

INSERT INTO Sys_DbLog(LogTime, Type, Item, Message, Remark) VALUES(GETDATE(), 'info', 'SP_Add_CustomerNewOpening', '存储过程执行开始', NULL);

DECLARE @RewardsMoney decimal(18,2) = CAST(ISNULL((SELECT Value FROM Config WHERE Id=79), '0') AS decimal(18,2));

DECLARE @NewOpenMoney decimal(18,2) = CAST(ISNULL((SELECT Value FROM Config WHERE Id=80), '0') AS decimal(18,2));

DECLARE @AddCustNewOpenCount int = 0, @AddOrderNewOpenCount int = 0, @UpdateCustNewOpenCount int = 0,

@UpdateOrderNewOpenCount int = 0, @UpdateRefundmentCount int = 0;

BEGIN TRY

BEGIN TRANSACTION;

--1. 新增新开客户

DECLARE @OrderNewOpenId int, @CustNewOpenId int;

DECLARE @UserId bigint, @PayTime datetime, @Address nvarchar(500), @CustomerId bigint, @EmplCityId int, @EmployeeId int, @RealTotal decimal(18,2);

DECLARE cursor_CustomerNewOpening CURSOR GLOBAL SCROLL DYNAMIC SCROLL_LOCKS

FOR SELECT UserId, PayTime, Address, CustomerId, EmplCityId, EmployeeId, SUM(RealTotal) AS RealTotal FROM

(

SELECT t1.UserId, t1.PayTime, t1.Address, t2.CustomerId, t4.CityId AS EmplCityId, t4.EmployeeId, t1.RealTotal FROM Orders AS t1

INNER JOIN UserInfo AS t2 ON(t1.UserId = t2.Id)

INNER JOIN Customer AS t3 ON(t2.CustomerId = t3.Id)

INNER JOIN Sys_EmployeeProfile AS t4 ON(t1.SalesUserId = t4.EmployeeId)

WHERE 1=1

AND t1.UserId > 0

AND t2.CustomerId > 0

AND t1.SalesUserId > 0

AND (t1.OrderStatusId > 1 AND t1.OrderStatusId < 10)

AND (t1.PayStatusId = 2 AND t1.PayTime >= @StartTime AND t1.PayTime <= @EndTime)

AND NOT EXISTS(SELECT TOP 1 1 FROM Crm_CustomerNewOpening AS T WHERE T.CustomerId = t2.CustomerId AND (T.NewOpenStatus = 1 OR T.NewOpenStatus = 4))

AND NOT EXISTS(SELECT TOP 1 1 FROM Crm_OrderNewOpening AS T WHERE T.OrderId = t1.Id)

) AS T WHERE 1=1

AND RealTotal >= @NewOpenMoney

GROUP BY UserId, PayTime, Address, CustomerId, EmplCityId, EmployeeId;

OPEN cursor_CustomerNewOpening;

FETCH FIRST FROM cursor_CustomerNewOpening INTO @UserId, @PayTime, @Address, @CustomerId, @EmplCityId, @EmployeeId, @RealTotal;

WHILE(@@FETCH_STATUS = 0)

BEGIN

--防止本次执行多条符合的情况

IF(NOT EXISTS(SELECT TOP 1 1 FROM Crm_CustomerNewOpening AS T WHERE T.CustomerId = @CustomerId AND (T.NewOpenStatus = 1 OR T.NewOpenStatus = 4)))

BEGIN

--插入客户新开

INSERT INTO Crm_CustomerNewOpening(CustomerId, EmplCityId, EmployeeId, RewardsMoney, NewOpenMoney, RealTotal,

RefundmentMoney, PayTime, NewOpenStatus, AuditorId, AuditorTime, AuditDesc, CreateTime, UpdateTime)

VALUES(@CustomerId, @EmplCityId, @EmployeeId, @RewardsMoney, @NewOpenMoney, @RealTotal,

0, @PayTime, 1/*当前有效*/, NULL, NULL, NULL, GETDATE(), NULL);

SELECT @CustNewOpenId = SCOPE_IDENTITY(), @AddCustNewOpenCount = (@AddCustNewOpenCount + @@ROWCOUNT);

--插入订单新开

INSERT INTO Crm_OrderNewOpening(CustNewOpenId, OrderId, OrderNum, RealTotal, RefundmentMoney, CreateTime, UpdateTime)

SELECT @CustNewOpenId, t1.Id, t1.OrderNum, t1.RealTotal, 0, GETDATE(), NULL FROM Orders AS t1

WHERE 1=1

AND t1.UserId = @UserId

AND t1.PayTime = @PayTime

AND t1.Address = @Address;

SELECT @AddOrderNewOpenCount = (@AddOrderNewOpenCount + @@ROWCOUNT);

END

FETCH NEXT FROM cursor_CustomerNewOpening INTO @UserId, @PayTime, @Address, @CustomerId, @EmplCityId, @EmployeeId, @RealTotal;

END

CLOSE cursor_CustomerNewOpening;

DEALLOCATE cursor_CustomerNewOpening;

--2. 更新客户新开（退款失效）

DECLARE @RefundmentId int, @OrderId bigint, @RefundmentMoney decimal(18,2);

DECLARE cursor_Crm_Refundment CURSOR GLOBAL SCROLL DYNAMIC SCROLL_LOCKS

FOR SELECT Id, OrderId, RefundmentMoney FROM Crm_Refundment AS t1 WHERE t1.OrderNewOpenId IS NULL

AND t1.CreateTime >= @StartTime AND t1.CreateTime <= @EndTime

FOR UPDATE OF OrderNewOpenId, UpdateTime;

OPEN cursor_Crm_Refundment;

FETCH FIRST FROM cursor_Crm_Refundment INTO @RefundmentId, @OrderId, @RefundmentMoney;

WHILE(@@FETCH_STATUS = 0)

BEGIN

SELECT @OrderNewOpenId = NULL, @CustNewOpenId = NULL;

SELECT @OrderNewOpenId = Id, @CustNewOpenId = CustNewOpenId FROM Crm_OrderNewOpening WHERE OrderId = @OrderId;

IF(@OrderNewOpenId IS NOT NULL AND @CustNewOpenId IS NOT NULL)

BEGIN

DECLARE @RowCount1 int = 0, @RowCount2 int = 0;

--1. 更新订单新开

UPDATE Crm_OrderNewOpening SET RefundmentMoney = (RefundmentMoney + @RefundmentMoney), UpdateTime = GETDATE()

WHERE Id = @OrderNewOpenId;

SELECT @RowCount1 = @@ROWCOUNT, @UpdateOrderNewOpenCount = (@UpdateOrderNewOpenCount + @@ROWCOUNT);

--2. 更新客户新开

UPDATE Crm_CustomerNewOpening SET RefundmentMoney = (RefundmentMoney + @RefundmentMoney),

NewOpenStatus = (CASE WHEN NewOpenStatus = 1 AND (RealTotal - (RefundmentMoney + @RefundmentMoney)) < @NewOpenMoney

THEN 2 ELSE NewOpenStatus END)/*只有【当前有效】状态才更新状态*/,

RefundmentId = (CASE WHEN NewOpenStatus = 1 AND (RealTotal - (RefundmentMoney + @RefundmentMoney)) < @NewOpenMoney

--AND RefundmentId IS NULL/*逻辑上可以省略该条件，因为。。。*/

THEN @RefundmentId ELSE RefundmentId END)/*记录导致退款失效的退款Id*/,

UpdateTime = GETDATE()

WHERE Id = @CustNewOpenId;

SELECT @RowCount2 = @@ROWCOUNT, @UpdateCustNewOpenCount = (@UpdateCustNewOpenCount + @@ROWCOUNT);

IF(@RowCount1 = 1 AND @RowCount2 = 1)

BEGIN

UPDATE Crm_Refundment SET OrderNewOpenId = @OrderNewOpenId, UpdateTime = GETDATE() WHERE CURRENT OF cursor_Crm_Refundment;

SELECT @UpdateRefundmentCount = (@UpdateRefundmentCount + @@ROWCOUNT);

END

END

FETCH NEXT FROM cursor_Crm_Refundment INTO @RefundmentId, @OrderId, @RefundmentMoney;

END

CLOSE cursor_Crm_Refundment;

DEALLOCATE cursor_Crm_Refundment;

COMMIT;

SET @Remark = '新开客户数：' + CAST(@AddCustNewOpenCount AS varchar(20))

+ '，新开订单数：' + CAST(@AddOrderNewOpenCount AS varchar(20))

+ '，更新新开客户数：' + CAST(@UpdateCustNewOpenCount AS varchar(20))

+ '，更新新开订单数：' + CAST(@UpdateOrderNewOpenCount AS varchar(20))

+ '，更新退款数：' + CAST(@UpdateRefundmentCount AS varchar(20));

INSERT INTO Sys_DbLog(LogTime, Type, Item, Message, Remark) VALUES(GETDATE(), 'info', 'SP_Add_CustomerNewOpening', '存储过程执行结束', @Remark);

END TRY

BEGIN CATCH

ROLLBACK;

DECLARE @Message varchar(8000) = '错误：[' + CAST(ERROR_LINE() AS nvarchar(20)) + ']，' + ERROR_MESSAGE();

INSERT INTO Sys_DbLog(LogTime, Type, Item, Message, Remark) VALUES(GETDATE(), 'error', 'SP_Add_CustomerNewOpening', @Message, '事物已回滚');

END CATCH

GO