Get default serial value after INSERT inside PL/pgSQL

问题

I have a table. I wrote a function in plpgsql that inserts a row into this table:

INSERT INTO simpleTalbe (name,money) values('momo',1000) ;

This table has serial field called id. I want in the function after I insert the row to know the id that the new row received.

I thought to use:

select nextval('serial');

before the insert, is there a better solution?

回答1:

Use the RETURNING clause. You need to save the result somewhere inside PL/pgSQL - with an appended INTO ..

INSERT INTO simpleTalbe (name,money) values('momo',1000)
RETURNING id
INTO _my_id_variable;

_my_id_variable must have been declared with a matching data type.

PostgreSQL next value of the sequences?

Depending on what you plan to do with it, there is often a better solution with pure SQL. Examples:

Combining INSERT statements in a data-modifying CTE with a CASE expression
PostgreSQL multi INSERT...RETURNING with multiple columns

回答2:

select nextval('serial'); would not do what you want; nextval() actually increments the sequence, and then the INSERT would increment it again. (Also, 'serial' is not the name of the sequence your serial column uses.)

@Erwin's answer (INSERT ... RETURNING) is the best answer, as the syntax was introduced specifically for this situation, but you could also do a

SELECT currval('simpletalbe_id_seq') INTO ...

any time after your INSERT to retrieve the current value of the sequence. (Note the sequence name format tablename_columnname_seq for the automatically-defined sequence backing the serial column.)

来源：https://stackoverflow.com/questions/33837643/get-default-serial-value-after-insert-inside-pl-pgsql

标签

postgresql

plpgsql

sql-insert

sql-returning

nextval