PostgreSQL：如何在数据库的每个表中添加一列？

Question

I have a database with 169 tables

I need this column in every table:

wid integer not null primary key

I tried this(Thanks https://stackoverflow.com/users/27535/gbn for the solution):

SELECT 
  'ALTER TABLE ' + T.name + ' ADD foo int NULL'
FROM
  sys.tables AS T
WHERE
  T.is_ms_shipped = 0

But it didn't work on PostgreSQL.

It only worked on tsql.

How to add this column in every table at once ?

Answer 1

do $$
declare
    selectrow record;
begin
for selectrow in
    select 
      'ALTER TABLE '|| T.mytable || ' ADD COLUMN foo integer NULL' as script 
   from 
      ( 
        select tablename as mytable from  pg_tables where schemaname  ='public' --your schema name here
      ) t
loop
execute selectrow.script;
end loop;
end;
$$;

---

You can test whether all your tables altered with the new column using the following select

select 
     table_name,COLUMN_NAME
 from 
     INFORMATION_SCHEMA.COLUMNS 
 where 
   COLUMN_NAME='foo' -- <whatever your column name here>

Answer 2

Try this (change 'public' to whatever schema you're doing this in)

DO $$
DECLARE 
    row record; 
    cmd text;
BEGIN
    FOR row IN SELECT schemaname, tablename FROM pg_tables WHERE schemaname = 'public' LOOP
        cmd := format('ALTER TABLE %I.%I ADD COLUMN foo SERIAL PRIMARY KEY ', row.schemaname, row.tablename);
        RAISE NOTICE '%', cmd;
        -- EXECUTE cmd;
    END LOOP;
END
$$ LANGUAGE plpgsql;

If you run as is, it'll show you the commands. Uncomment the EXECUTE line to actually perform the alterations.

I'd run within a transaction so you can roll back if you're not happy with the results.

Note that the type is SERIAL - the column type will be integer, but also creates a sequence owned by the table and defaults the column value to the next value of that sequence.

Answer 3

We may need to check column is already exist or not .

Tested on PostgreSQL V10

do $$
declare selectrow record;
begin
for selectrow in
    select 'ALTER TABLE '|| T.mytable || ' ADD COLUMN x_is_exported boolean DEFAULT FALSE' as script 
   from (select tablename as mytable from  pg_tables where schemaname  ='public') t
loop
    begin
        execute selectrow.script;
        EXCEPTION WHEN duplicate_column THEN CONTINUE;
    END;
end loop;
end;
$$;