Renaming multiple columns in PostgreSQL

My table has a bunch of columns in the following format:

_settingA
_settingB
_settingB

And I want to rename them simply to add a prefix as follows:

_1_settingA
_1_settingB
_1_settingC

What is the quickest / most efficient way to achieve this?

EDIT: I should add that I have a lot more than three columns to rename in this way. If I had just three, I'd just do it manually one by one. And thanks for the downvote whoever you are.

Gabriel's Messanger

There's no single command aproach. Obviously you could type multiple comands for RENAME by your self, but let me intoduce some improvement:) As I said in this answer

...for all such bulk-admin-operations you could use PostgreSQL system tables to generate queries for you instead of writing them by hand

In your case it would be:

SELECT
    'ALTER TABLE ' || tab_name || ' RENAME COLUMN '
    || quote_ident(column_name) || ' TO '
    || quote_ident( '_1' || column_name) || ';'
FROM (
    SELECT
        quote_ident(table_schema) || '.' || quote_ident(table_name) as tab_name,
        column_name
    FROM information_schema.columns  
    WHERE 
            table_schema = 'schema_name'
            AND table_name = 'table_name'
            AND column_name LIKE '\_%'
) sub;

That'll give you set of strings which are SQL commands like:

ALTER TABLE  schema_name.table_name RENAME COLUMN "_settingA" TO "_1_settingA";
ALTER TABLE  schema_name.table_name RENAME COLUMN "_settingB" TO "_1_settingB";
...

There no need using table_schema in WHERE clause if your table is in public schema. Also remember using function quote_ident() -- read my original answer for more explanation.

Edit:

I've change my query so now it works for all columns with name begining with underscore _. Because underscore is special character in SQL pattern matching, we must escape it (using \) to acctually find it.

Something simple like this will work.

SELECT FORMAT(
  'ALTER TABLE %I.%I.%I RENAME %I TO %I;',
  table_catalog,
  table_schema,
  table_name,
  column_name,
  '_PREFIX_' + column_name
)
FROM information_schema.columns
WHERE table_name = 'foo';

%I will do quote_ident, which is substantially nicer. If you're in PSQL you can run it with \gexec

You can't do that.

All the actions except RENAME and SET SCHEMA can be combined into a list of multiple alterations to apply in parallel.

most efficient way is using ActiveRecord.

来源：https://stackoverflow.com/questions/33401404/renaming-multiple-columns-in-postgresql

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