SQL Return Table with where clause and occurrences of value of total table

I am stumped trying to figure out how to achieve this. I know how I would achieve it in C#, but not SQL.

Say I have the following table:

ID
Name
RouteId

1
Bob
1001

2
Bob
1002

3
Ana
1001

4
Jim
1001

5
Eli
1001

I would like to return the entire table, with an extra column showing the total occurrences of routeID by name, so where name='Bob' looks like:

ID
Name
RouteId
Total

1
Bob
1001
4

2
Bob
1002
1

However, if I write something like

declare @ct as nvarchar(5)
set @ct = (SELECT COUNT(RouteId) from )

select *, @ct
from 
where name = 'Bob'

I get the total number of ALL route IDs, not just the one displayed in the row.

I tried looking into computed columns but from what I can see it doesn't support this type of query.

Can anyone point me in the right direction?

You can use a windowed COUNT inside a derived table (subquery)

SELECT *
FROM (
    SELECT *,
      Total = COUNT(*) OVER (PARTITION BY t.RouteId)
    FROM MyTable t
) t
WHERE t.Name = 'Bob';

db<>fiddle

StackExchange Database Administrators Q#313941, answer score: 9