?? 簡介

本文主要記錄 MSSQL 中的游標使用示例，在有必要時方便借鑒查閱。游標一般定義在某段功能性的 SQL 語句中，或者存儲過程中。之所以選擇用它，是因為有時候無法使用簡單的 SQL 語句滿足我們需求，比如需要對結果集中的每一條數據，根據不同條件進行不同操作（CRUD），這時我們就可以使用游標來完成。

提示：來之 DBA 的杰作，哈哈~~

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1.?? 示例1：

本示例，用于初始化某新表的數據。使用游標遍歷查詢結果集，根據遍歷的數據再插入另外兩張表。SQL 代碼如下：

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

??? DROP PROCEDURE SP_Init_CustomerNewOpening;

GO

CREATE PROCEDURE SP_Init_CustomerNewOpening

AS

??? INSERT INTO Sys_DbLog(LogTime, Type, Item, Message, Remark) VALUES(GETDATE(), 'info', 'SP_Init_CustomerNewOpening', '存儲過程執行開始', NULL);

??? BEGIN TRY

??????? BEGIN TRANSACTION;

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

??????? DECLARE @NewOpenMoney decimal(18,2) = 0;

??????? DECLARE @CustNewOpenId int;

??????? DECLARE @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 PayTime, Address, CustomerId, EmplCityId, EmployeeId, SUM(RealTotal) AS RealTotal FROM

??????? (

??????????? SELECT t1.PayTime, t1.Address, t1.CustomerId, t1.EmplCityId, t1.EmployeeId, t2.RealTotal FROM

??????????? (

??????????????? SELECT t2.PayTime, t2.Address, t1.Id AS CustomerId, t3.CityId AS EmplCityId, t3.EmployeeId FROM Customer AS t1

??????????????? INNER JOIN Orders AS t2 ON(t1.BdBonus = t2.Id)

??????????????? INNER JOIN Sys_EmployeeProfile AS t3 ON(t2.SalesUserId = t3.EmployeeId)

??????????????? WHERE t1.BdBonus > 0

??????????? ) AS t1

??????????? INNER JOIN Orders AS t2 ON(t1.PayTime = t2.PayTime AND t1.Address = t2.Address)

??????????? WHERE 1=1

??????????? --,Orders AS t2

??????????? --WHERE t1.PayTime = t2.PayTime AND t1.Address = t2.Address

??????? ) AS T WHERE 1=1

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

??????? OPEN cursor_CustomerNewOpening;

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

??????? DECLARE @dt datetime = '2018-06-01 00:00:00';

??????? WHILE(@@FETCH_STATUS = 0)

??????? BEGIN

??????????? IF((@PayTime >= @dt AND @RealTotal >= 999) OR (@PayTime < @dt AND @RealTotal >= 699))

??????????? BEGIN??????????

??????????????? --插入客戶新開

??????????????? SET @NewOpenMoney = CASE WHEN @RealTotal >= 999 THEN 999 WHEN @RealTotal >= 699 THEN 699 ELSE @RealTotal END;

??????????????? 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, 4/*歷史有效*/, NULL, NULL, NULL, GETDATE(), NULL);

??????????????? SET @CustNewOpenId = SCOPE_IDENTITY();

???????????

??????????????? --插入訂單新開

??????????????? 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.PayTime = @PayTime

??????????????? AND t1.Address = @Address;

??????????? END

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

??????? END

??????? CLOSE cursor_CustomerNewOpening;

??????? DEALLOCATE cursor_CustomerNewOpening;

??????? COMMIT;

??????? INSERT INTO Sys_DbLog(LogTime, Type, Item, Message, Remark) VALUES(GETDATE(), 'info', 'SP_Init_CustomerNewOpening', '存儲過程執行結束', NULL);

??? END TRY

??? BEGIN CATCH

??????? ROLLBACK;

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

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

??? END CATCH

GO

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2.?? 示例2：

1)?? 本示例，創建了一個存儲過程，創建了兩個游標。

2)?? 第一個游標，使用游標完成更新遍歷的記錄，再使用遍歷的數據完成對另外兩張表的 Insert 操作。

3)?? 第二個游標，完成對3張表的更新操作，在示例中使用了當前游標記錄作為更新條件，例如：WHERE CURRENT OF cursor_Crm_Refundment。

4)?? 該存儲過程用于定時任務執行，比在程序中去查詢數據，然后再遍歷寫入數據效率上還是比較有優勢的，而且便于維護。SQL 代碼如下：

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

??? DROP PROCEDURE SP_Add_CustomerNewOpening;

GO

CREATE PROCEDURE SP_Add_CustomerNewOpening

(

??? @StartTime datetime,??????????????? --開始時間

??? @EndTime datetime?????????????????? --結束時間

)

AS

??? DECLARE @Remark varchar(8000) = NULL;

??? INSERT INTO Sys_DbLog(LogTime, Type, Item, Message, Remark) VALUES(GETDATE(), 'info', 'SP_Add_CustomerNewOpening', '存儲過程執行開始', 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;

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??????? --1. 新增新開客戶

??????? 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

??????????? --防止本次執行多條符合的情況

??????????? 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

??????????????? --插入客戶新開

??????????????? 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/*當前有效*/, NULL, NULL, NULL, GETDATE(), NULL);

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

???????????

??????????????? --插入訂單新開

??????????????? 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;

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??????? --2. 更新客戶新開（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. 更新訂單新開

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

??????????????? WHERE Id = @OrderNewOpenId;

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

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??????????????? --2. 更新客戶新開

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

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

??????????????????????? THEN 2 ELSE NewOpenStatus END)/*只有【當前有效】狀態才更新狀態*/,

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

??????????????????????????? --AND RefundmentId IS NULL/*邏輯上可以省略該條件，因為。。。*/

??????????????????????? THEN @RefundmentId ELSE RefundmentId END)/*記錄導致退款失效的退款Id*/,

??????????????????? UpdateTime = GETDATE()

??????????????? WHERE Id = @CustNewOpenId;

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

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??????????????? 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 = '新開客戶數：' + CAST(@AddCustNewOpenCount AS varchar(20))

??????????? + '，新開訂單數：' + CAST(@AddOrderNewOpenCount AS varchar(20))

??????????? + '，更新新開客戶數：' + CAST(@UpdateCustNewOpenCount AS varchar(20))

??????????? + '，更新新開訂單數：' + CAST(@UpdateOrderNewOpenCount AS varchar(20))

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

??????? INSERT INTO Sys_DbLog(LogTime, Type, Item, Message, Remark) VALUES(GETDATE(), 'info', 'SP_Add_CustomerNewOpening', '存儲過程執行結束', @Remark);

??? END TRY

??? BEGIN CATCH

??????? ROLLBACK;

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

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

??? END CATCH

GO

轉載于:https://www.cnblogs.com/abeam/p/9929203.html

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