Rails migrations - change_column with type conversion

Question

I already google\'d aroung a little bit and seems there\'s no satisfying answer for my problem.

I have a table with column of type string. I\'d like to run following

Answer 1

Since I'm using Postgres, I went with SQL solution for now. Query used:

    execute 'ALTER TABLE "users" ALTER COLUMN "smoking" TYPE boolean USING CASE WHEN "flatshare"=\'true\' THEN \'t\'::boolean ELSE \'f\'::boolean END'

It works only if one has a field filled with true/false strings (such as default radio button collection helper with forced boolean type would generate)