How to fill/insert fake data into a MS Sql Server
Do a CROSS JOIN between sys.columns, use that same 2, 3 , or 4 times. Have a TOP, with as many rows as you want. Use that as a base for INSERT ... SELECT.

CREATE TABLE mytable(c1 int identity(1, 1), c2 char(10))

INSERT INTO mytable
SELECT TOP(1000) 'Hello'
FROM sys.columns AS a 
 CROSS JOIN sys.columns AS b 
 CROSS JOIN sys.columns AS c


The cross join is a classic trick. Do a cross join between two tables that has 1000 rows each and you have 1,000,000 rows in the result. With 3 tables, you have 1,000,000,000 rows. You can have some "numbers" table you create for these purposes, with for instance 1000 rows in it. Or, do a quick and dirty and use some view that you know exists with a decent amount or rows in it (like sys.columns).