ORA-00904 'invalid identifier' error using 'MERGE INTO' and 'SELECT FROM dual' on a DATE column

Question

I have the following PL/SQL stored procedure on an Oracle database:

PROCEDURE MyProcedure (
    p_id IN NUMBER
  , p_date IN DATE
  , p_num IN NUMBER) 
  AS
  BEGIN
    MERGE INTO MY_TABLE mytable
    USING (SELECT
            p_id,
            p_date,
            p_num
          FROM dual) temp
    ON (mytable.myid = temp.p_id AND mytable.mydate = temp.p_date)
  WHEN MATCHED THEN
    UPDATE SET
      DIFFERENCE = temp.p_num,
  WHEN NOT MATCHED THEN
    INSERT VALUES (
      MY_TABLEIDSEQ.NEXTVAL,
      temp.p_id,
      temp.p_date,
      temp.p_num);
END MyProcedure;

The MY_TABLE table is defined as follows:

CREATE TABLE "MY_DBO"."MY_TABLE" 
   (
     "MYTABLEID" NUMBER(38,0),
     "MYID" NUMBER(38,0),
     "MYDATE" DATE,
     "MYNUM" NUMBER(25,4)
   )

However, when I run the stored procedure with valid values for the input fields, I get the following error:

ORA-00904: "TEMP"."P_DATE": invalid identifier

ORA-06512: at "MY_DBO.MY_PKG", line 54

ORA-06512: at line 18

I've no idea what is causing this, any help would be greatly appreciated. Please note that the stored procedure begins on line 45 of MY_PKG.

I found a similar issue here, but the solution to change 'dual' to 'MY_TABLE' didn't seem to work for me.

PS: I am very new to Oracle :)

Answer 1

In the "select from dual" statement you used the input parameters of your stored procedures as values. Oracle indeed generates implicit names for these columns, which I cannot currently predict. But you could provide your own column names/alias names in that statement:

USING (SELECT
        p_id col_id,
        p_date col_date,
        p_num col_num
      FROM dual) temp

Those names are just examples. I would strongly encourage you to use unique names in such a case to prevent any ambiguities later on. You would need to replace any use of temp.* in your merge statement with the alias names you provided.

Answer 2

This won't really answer your question since it has alreasy been answered by Juergen Hartelt but it will provide you some more information.

Since you are only inserting or updating one row here, another option might be to forego the use of MERGE and use a combination of INSERT and UPDATE instead.

In your case, you would use

PROCEDURE MyProcedure (
    p_id IN NUMBER
  , p_date IN DATE
  , p_num IN NUMBER) 
  AS
  BEGIN
    Update MY_TABLE mytable
    Set MYNUM = p_num
    Where mytable.MYID = p_id AND mytable.MYDATE = p_date;

    If SQL%ROWCOUNT = 0 then
      INSERT INTO MY_TABLE mytable 
      Values (MY_TABLEIDSEQ.NEXTVAL,
      temp.p_id,
      temp.p_date,
      temp.p_num);
    END IF;

END MyProcedure;

Also, it might be worth looking at the question "How to UPSERT" since that will provide you the complete menu of options to solve this problem.