Pick random number within a range

Pick random number within a range

I have a table (TableA) with an integer column(ColumnA) and there is data
already in the table. Need to write a select statement to insert into this
table with the integer column having random values within 5000. This value
should not already be in columnA of TableA
Insert into TableA (columnA,<collist....>)
SELECT <newColId> ,<collist....> from TableB <where clause>