I have small database with few text fields with "default" collation. I don't want to recreate database. What is the query to alter all problematic fields at once?

To change the single one I can use

ALTER TABLE a_table_name ALTER a_column_name TYPE text COLLATE a_collate;
  • 1
    You can loop over the columns in a DO block, for example, constructing and executing a dynamic query. Dec 4, 2013 at 15:12

1 Answer 1


There isn't a single SQL command that will do that for you. You can write a loop in a different language, using the results from

SELECT table_name, column_name
  FROM information_schema.columns
  WHERE table_schema IN ('your_schemas')
    AND data_type = 'text'
    AND collation_name IS NULL;

or similar.

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