Sequence does not reset after truncating the table

Question

I use SELECT lastval() to get wrong serial id after truncated the table.

when I truncate the table, I use SELECT lastval(), I got the wrong ID/

Answer 1

Following is the standard way to reset sequence:

truncate table table_name restart identity; 

but in some version & platform, it's syntax error,

in that case, you can truncate without reset sequence, and alter the sequence with another sql, try this:

truncate table table_name; alter sequence seq_name start 1; 

Answer 2

Use the TRUNCATE SQL command.

For a single table the syntax is the following:

TRUNCATE TABLE table_name RESTART IDENTITY; 

For multiple tables:

TRUNCATE TABLE table_foo, table_bar RESTART IDENTITY; 

What it does:

Automatically restart sequences owned by columns of the truncated table(s).

Details here: TRUNCATE @ postgresql.org