使用更新或插入语句添加到整数值

Question

我试图在 Firebird 2.5 中创建一个 SQL 语句，以便通过在记录存在时添加或简单地插入新行来更新整数数量。如果某个数量已经存在，我似乎无法找到有关添加到某个数量的具体问题的真正答案。

我能想到的 SQL 如下：

UPDATE OR INSERT INTO Pencils(Number, Location, Quantity)
VALUES('12345678/90', 'TOP', 20)
MATCHING(Number, Location);

因此，如果有匹配的记录，我想在实际 20 数量中添加一定数量。

就像我对UPDATE声明所做的那样：

UPDATE Pencils SET Quantity = Quantity + 20 WHERE Number = '12345678/90' 

是否有可能通过UPDATE OR INSERT语句达到这样的结果，或者还有其他方法吗？. .

编辑： 与 IBExpert/Delphi 参数一起使用的查询的解决方案

MERGE INTO Pencils AS Dest
USING (SELECT CAST(:myNumb as varchar(30))  AS Number,
              CAST(:myLoca as varchar(10))  AS Location,
              CAST(:myQuan as integer)  AS Quantity
        FROM RDB$DATABASE) Src
    ON (Dest.Number = Src.Number AND Dest.Location = Src.Location)
WHEN MATCHED THEN
   UPDATE SET Dest.Quantity = Dest.Quantity + Src.Quantity
WHEN NOT MATCHED THEN
   INSERT (Number, Location, Quantity) VALUES (Src.Number, Src.Location, Src.Quantity);

Answer 1

将 Firebird 的MERGE用于复杂的 UPSERT：

MERGE INTO Pencils AS Dest
USING (SELECT '12345678/90' AS Number,
              'TOP'         AS Location,
              20            As Quantity
         FROM RDB$DATABASE) Src
   ON (Dest.Number = Src.Number AND Dest.Location = Src.Location)
WHEN MATCHED THEN
   UPDATE SET Dest.Quantity = Dest.Quantity + 10
WHEN NOT MATCHED THEN
   INSERT (Number, Location, Quantity) VALUES (Src.Number, Src.Location, Src.Quantity);

这里唯一的复杂性是您Quantity在 UPDATE 上动态计算。如果您只是用静态值覆盖现有记录，则可以更简洁地使用UPDATE OR INSERT。

例子：

SQL> SELECT * FROM Pencils;

NUMBER               QUANTITY LOCATION         
================ ============ ================ 
123                         5 TOP              
123                        10 MID              

SQL> MERGE INTO Pencils AS Dest
CON> USING (SELECT '123' AS Number, 'TOP' AS Location, 20 As Quantity
CON> FROM RDB$DATABASE) Src ON (Dest.Number = Src.Number AND Dest.Location = Src.Location)
CON> WHEN MATCHED THEN
CON>    UPDATE SET Dest.Quantity = Dest.Quantity + 10
CON> WHEN NOT MATCHED THEN
CON>    INSERT (Number, Location, Quantity) VALUES (Src.Number, Src.Location, Src.Quantity);

SQL> SELECT * FROM Pencils;

NUMBER               QUANTITY LOCATION         
================ ============ ================ 
123                        15 TOP              
123                        10 MID              

SQL> SELECT * FROM Pencils;

NUMBER               QUANTITY LOCATION         
================ ============ ================ 
123                         5 TOP              
123                        10 MID              

SQL> MERGE INTO Pencils AS Dest
CON> USING (SELECT '123' AS Number, 'TOP' AS Location, 20 As Quantity
CON> FROM RDB$DATABASE) Src ON (Dest.Number = Src.Number AND Dest.Location = Src.Location)
CON> WHEN MATCHED THEN
CON>    UPDATE SET Dest.Quantity = Dest.Quantity + 10
CON> WHEN NOT MATCHED THEN
CON>    INSERT (Number, Location, Quantity) VALUES (Src.Number, Src.Location, Src.Quantity);

SQL> SELECT * FROM Pencils;

NUMBER               QUANTITY LOCATION         
================ ============ ================ 
123                        15 TOP              
123                        10 MID              
123                        20 BOT