Проблема с триггером Запрос вернул больше одного значения

CREATE TRIGGER insert_item
ON TRANSFERS AFTER INSERT
AS
DECLARE @I_ID INT,@L_O INT,@L_I INT,@I_COUNT INT,@I_C INT;
BEGIN
 SELECT @I_ID=ITEM_ID FROM inserted;
 SELECT @L_O=LOC_OUT FROM inserted;
 SELECT @L_I=LOC_IN FROM inserted;
 SELECT @I_COUNT=ITEM_COUNT FROM inserted;
 
 IF (@I_ID=(SELECT ITEM_ID FROM ITEMS WHERE ITEM_ID=@I_ID) AND @L_O=(SELECT LOCATION_ID FROM ITEMS WHERE LOCATION_ID=@L_O))
 
 BEGIN
    SELECT @I_C=ITEM_COUNT-@I_COUNT FROM ITEMS WHERE LOCATION_ID=@L_O;
    UPDATE ITEMS SET ITEM_COUNT=@I_C
    WHERE ITEM_ID=@I_ID AND LOCATION_ID=@L_O;
    INSERT ITEMS VALUES (@I_ID,@L_I,@I_COUNT);
 END
 
IF (@I_ID=(SELECT ITEM_ID FROM ITEMS WHERE ITEM_ID=@I_ID) AND (@L_I=(SELECT LOCATION_ID FROM ITEMS WHERE LOCATION_ID=@L_I)))
 
 BEGIN
    SELECT @I_C=ITEM_COUNT+@I_COUNT FROM ITEMS WHERE LOCATION_ID=@L_O;
    UPDATE ITEMS SET ITEM_COUNT=@I_C 
    WHERE ITEM_ID=@I_ID AND LOCATION_ID=@L_I;
    INSERT ITEMS VALUES (@I_ID,@L_I,@I_COUNT);
 END
 
 IF (@I_ID!=(SELECT ITEM_ID FROM ITEMS WHERE ITEM_ID=@I_ID))
 BEGIN
    INSERT ITEMS VALUES (@I_ID,@L_I,@I_COUNT);
 END
END