List all sequences in a Postgres db 8.1 with SQL

Question

I\'m converting a db from postgres to mysql.

Since i cannot find a tool that does the trick itself, i\'m going to convert all postgres sequences to autoincrement id

Answer 1

The following query gives names of all sequences.

SELECT c.relname FROM pg_class c WHERE c.relkind = 'S';

Typically a sequence is named as ${table}_id_seq. Simple regex pattern matching will give you the table name.

To get last value of a sequence use the following query:

SELECT last_value FROM test_id_seq;

Answer 2

Kind of a hack, but try this:

select 'select ''' || relname || ''' as sequence, last_value from ' || relname || ' union' FROM pg_catalog.pg_class c WHERE c.relkind IN ('S','');

Remove the last UNION and execute the result

Answer 3

Run: psql -E, and then \ds

Answer 4

after a little bit of pain, i got it.

the best way to achieve this is to list all tables

select * from pg_tables where schemaname = '<schema_name>'

and then, for each table, list all columns with attributes

select * from information_schema.columns where table_name = '<table_name>'

then, for each column, test if it has a sequence

select pg_get_serial_sequence('<table_name>', '<column_name>')

and then, get the information about this sequence

select * from <sequence_name>

Answer 5

Note, that starting from PostgreSQL 8.4 you can get all information about sequences used in the database via:

SELECT * FROM information_schema.sequences;

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Since I'm using a higher version of PostgreSQL (9.1), and was searching for same answer high and low, I added this answer for posterity's sake and for future searchers.

Answer 6

Improvement of the previous answer:

select string_agg('select sequence_name, last_value from ' || relname, chr(13) || 'union' || chr(13) order by relname) 
from pg_class where relkind ='S'