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：
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。
2) 注意：在游标开启后，如果在未关闭之前发生了异常，游标不能正常关闭，会导致该游标一直存在。所以，我们可以将游标定义在 TRY 语句之前，在 CATCH 语句中进行关闭。SQL 代码如下：
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', '存储过程执行开始', NULL);
BEGIN TRY
BEGIN TRANSACTION;
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
) 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;
WHILE(@@FETCH_STATUS = 0)
BEGIN
--插入客户新开
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/*历史有效*/, NULL, NULL, NULL, GETDATE(), NULL);
SET @CustNewOpenId = SCOPE_IDENTITY();
--插入订单新开
INSERT INTO Crm_OrderNewOpening(CustNewOpenId, OrderId, OrderNum, RealTotal, RefundmentMoney, CreateTime, UpdateTime)
SELECT 0, T1.Id, T1.OrderNum, T1.RealTotal, 0, GETDATE(), NULL FROM Orders AS T1
WHERE 1=1
AND T1.PayTime = @PayTime
AND T1.Address = @Address;
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', '存储过程执行结束', NULL);
END TRY
BEGIN CATCH
ROLLBACK;
DECLARE @Message varchar(8000) = '错误：行号[' + CAST(ERROR_LINE() AS nvarchar(20)) + ']，' + ERROR_MESSAGE();
INSERT INTO Sys_DbLog(LogTime, Type, Item, Message, Remark) VALUES(GETDATE(), 'error', 'SP_Init_CustomerNewOpening', @Message, '事物已回滚');
END CATCH
GO
2. 示例2：
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
INSERT INTO Sys_DbLog(LogTime, Type, Item, Message, Remark) VALUES(GETDATE(), 'info', 'SP_Add_CustomerNewOpening', '开始存储过程执行开始', 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));
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 1 FROM Crm_CustomerNewOpening AS T WHERE T.CustomerId = T2.CustomerId AND NOT(T.NewOpenStatus = 1 OR T.NewOpenStatus = 2))
) AS T WHERE 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
--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);
SET @CustNewOpenId = SCOPE_IDENTITY();
--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;
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 @OrderId bigint, @RefundmentMoney decimal(18,2);
DECLARE cursor_Crm_Refundment CURSOR GLOBAL SCROLL DYNAMIC SCROLL_LOCKS
FOR SELECT OrderId, RefundmentMoney FROM Crm_Refundment AS T1 WHERE T1.OrderNewOpenId IS NULL
AND T1.CreateTime >= @StartTime AND T1.CreateTime <= @EndTime
FOR UPDATE OF OrderNewOpenId;
OPEN cursor_Crm_Refundment;
FETCH FIRST FROM cursor_Crm_Refundment INTO @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 @NewOpenStatus int = (SELECT NewOpenStatus FROM Crm_CustomerNewOpening WHERE Id = @CustNewOpenId);
IF(@NewOpenStatus <> 4)
BEGIN
--1. 更新订单新开
UPDATE Crm_OrderNewOpening SET RefundmentMoney = (RefundmentMoney + @RefundmentMoney)
WHERE Id = @OrderNewOpenId;
DECLARE @RowCount1 int = @@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)
WHERE Id = @CustNewOpenId;
DECLARE @RowCount2 int = @@ROWCOUNT;
IF(@RowCount1 = 1 AND @RowCount2 = 1)
UPDATE Crm_Refundment SET OrderNewOpenId = @OrderNewOpenId WHERE CURRENT OF cursor_Crm_Refundment;
END
END
FETCH NEXT FROM cursor_Crm_Refundment INTO @OrderId, @RefundmentMoney;
END
CLOSE cursor_Crm_Refundment;
DEALLOCATE cursor_Crm_Refundment;
COMMIT;
INSERT INTO Sys_DbLog(LogTime, Type, Item, Message, Remark) VALUES(GETDATE(), 'info', 'SP_Add_CustomerNewOpening', '开始存储过程执行结束', NULL);
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