On duplicate key gives Invalid token

问题

I am trying to update name_code from employee_migration by numbers from cdclient from table clientref.

 INSERT INTO employee_migration (name_code)
      Select cl.cdclient 
        From clientref cl 
  Inner Join employee_migration em  
          ON cl.client like upper(em.name)
          ON DUPLICATE KEY UPDATE name_code VALUES (cl.cdclient)

I get this error: Invalid token.

Dynamic SQL Error.
SQL error code = -104.
Token unknown - line 3, column 1.
ON.

回答1:

If you use Firebird server (which was not said, but which looks like by your error text) then you have MERGE command for it.

However, if you use Interbase server, then I do not know how you can write that statement there, consult Interbase manuals then: http://docwiki.embarcadero.com/InterBase/2017/en/Statement_and_Function_Reference_(Language_Reference_Guide)

You can check the server you work with in IBExpert using Services -> Server Properties and Log menu.

Assuming you use Firebird version 2.1 or newer

http://en.wikipedia.org/wiki/Merge_(SQL)
https://www.firebirdsql.org/file/documentation/reference_manuals/fblangref25-en/html/fblangref25-dml-merge.html

For example something like this:

MERGE INTO employee_migration dest
USING (
      Select cl.cdclient, em.ID
        From clientref cl 
  Inner Join employee_migration em  
          ON cl.client like upper(em.name)
      ) as src
ON dest.ID = src.ID -- or whatever your key columns are

WHEN MATCHED THEN UPDATE SET dest.namecode = src.cdclient

WHEN NOT MATCHED THEN INSERT (namecode, ID, ....)
    VALUES ( src.cdclient, ...., ...........)

However without sample data your request seems of little practical sense.

Your join condition is cl.client like upper(em.name) - which is "many to many": for every row in clientref there can be many corresponding rows in employee_migration and vice versa.

So you would probably be matching and updating rows in employee_migration as dest with MANY candidate rows from the src query.

By SQL standard it should generate an immediate error.
By Firebird 2.x implementation - it would instead do those updates one after another, overwriting previous updates, and only the last candidate row would have their result persisted.

回答2:

Firebird has a different syntax than MySQL

MERGE INTO employee_migration
  USING (Select cl.cdclient 
    From clientref cl 
    Inner Join employee_migration em ON cl.client like upper(em.name)) AS tmp
  ON employee_migration.name_code = tmp.cdclient
  WHEN MATCHED THEN UPDATE SET name_code = tmp.cdclient
  WHEN NOT MATCHED THEN INSERT (name_code) VALUES(tmp.cdclient)

UPDATE

As @arioch-the properly pointed out you need the MERGE command. My original solution was actually wrong.

来源：https://stackoverflow.com/questions/51476351/on-duplicate-key-gives-invalid-token

标签

sql

firebird