Sql Server Begin TRY sample

BEGIN TRY
    BEGIN TRAN
    -- 业务操作
    INSERT INTO Products (ProductName, Price) VALUES ('新产品', 99.99)

    -- 数据验证
    IF EXISTS (SELECT 1 FROM Products WHERE ProductName = '新产品' AND Price < 100)
    BEGIN
        ;THROW 50001, '产品价格不能为负数', 1 
    END

    COMMIT TRAN
END TRY
BEGIN CATCH
    IF (@@TRANCOUNT > 0)
    begin
        ROLLBACK TRAN;--这里的分号一定要加
        THROW;
    END

END CATCH