how to do in console

i wish to select id from table where name = ‘fahim’

Table name is Info and columns are id and name

how to write a query in console

If you are talking about the console of MySQL query then you can write as below.

SELECT id FROM Info WHERE name = ‘fahim’

Else if you are talking about the ActiveRecord Query in rails then write it like this.

Info.select(“id”).where(:name => “fahim”)
This query would return you the ActiveRelation object containing the ids from Info where name is fahim.