Re: Strange primary key error on insertion

2011/10/6 Rory Campbell-Lange <rory(at)campbell-lange(dot)net>

> I have a strange issue (postgres 8.4) trying to insert old rows back
> into the s_tbls table. A check on the primary key (n_id) between
> s_tbl_import and s_tbls yields no matches, yet the index on s_tbls.n_id
> yields an error when attempting to insert:
>
> => select n_id from s_tbl_import where n_id IN (
> select n_id from s_tbls);
>
> n_id
> ------
> (0 rows)
>
> => insert into s_tbls (select * from s_tbl_import);
>
> ERROR: duplicate key value violates unique constraint "s_tbls_pkey"
>
>
Looks like you had duplicates in s_tbl_import. Try this:
SELECT * FROM s_tbl_import WHERE n_id IN (
SELECT n_id from s_tbl_import group by n_id HAVING count(*)>1
);

Table "s_tbls"
> Column | Type |
> Modifiers
>
> ------------------+-----------------------------+--------------------------------------------------------
> n_id | integer | not null default
> nextval('s_tbls_n_id_seq'::regclass)
> dt_created | timestamp without time zone | default now()
> dt_modified | timestamp without time zone | default now()
> t_node | text |
> ...
> Indexes:
> "s_tbls_pkey" PRIMARY KEY, btree (n_id)
>