Re: Converting char to varchar automatically

Hi!

>There really is no easy way to make a single ALTER for each table unless you use a programming language.

I’snt SQL a programming language ?

>However, adding a GROUP BY c.relname, a.attname
>would certainly simplify editing. Then you can combine all the
>ALTER COLUMN's for each table.

I wrote

with stem as (
SELECT 'ALTER TABLE ' || quote_ident(n.nspname) || '.'
|| quote_ident(c.relname) as prefix ,
string_agg(
' ALTER COLUMN ' || quote_ident(a.attname) || ' TYPE varchar(' || i.character_maximum_length ||')',
',' ) as body
FROM pg_class c
JOIN pg_namespace n ON n.oid = c.relnamespace
JOIN pg_attribute a ON a.attrelid = c.oid
JOIN pg_type t ON t.oid = a.atttypid
JOIN information_schema.columns i ON (i.table_name = c.relname AND i.column_name = a.attname)
WHERE t.typname = 'bpchar'
AND c.relkind = 'r'
AND n.nspname <> 'pg_catalog' and not attisdropped
group by 1
)

select prefix || ' '|| body || ';' as statement
from stem

Is this prefect ?

Andrus.