Re: Converting char to varchar automatically

>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