SQL Server select column while inserting - sql

Question

This question is a part of an insert statement in which I am trying to select a value from another value that can be inserted into a column.
For example in my table OnlineServers, I have columns:
ID, ServerID, OnlineSince
In my second table ImportServers, I have columns with the data (The lines after NewYork and Paris are actually empty):
ImportServerName
NewYork
London
Paris
Tokyo
This question is related to SQL Server.
In my third table, which is a look-up table called ServerLookup, I have these columns with data:
ID, ServerName
0 Not specified
1 NewYork
2 London
3 Tokyo
4 Munich
5 Salzburg
Question: I want to have an sql statement which can select ID '0' from ServerLookup table if the value of the column ImportServerName is empty.
What I have so far is:
insert into OnlineServers (ServerID, OnlineSince)
select
(
select ID
from ServerLookup
where ServerLookup.ServerName = ImportServers.ServerName
or ServerLookup.ServerName = ''
),
GETDATE()
from ImportServers
The problem I am facing is if the server name is matched, it also returns an extra row with empty server name.
How can I fix this problem.
Thanks
PS: Forgive me if there is any typo in the code

Answer 1

INSERT INTO OnlineServers
SELECT CASE ImportServerName
WHEN '' THEN 0
ELSE ID
END AS ServerID, GetDate()
FROM ImportedServers s
LEFT JOIN ServerLookup l on s.ImportedServerName = l.ServerName;
This should do it. You LEFT JOIN so you get every record from ImportedServers and use CASE to get 0 where ImportServerName is blank.

Answer 2

Maybe something like this:
SELECT FIRST(column_name) FROM table_name;
Limiting the return to the first match, also, shoudl teh from not be inside the select brackets?
select FIRST(ID)
from ServerLookup
where ServerLookup.ServerName = ImportServers.ServerName
or ServerLookup.ServerName = ''
from ImportServers)

Answer 3

if i understand your problem correctly try something like this
insert into OnlineServers (ServerID, OnlineSince)
select TOP(1) ID ,GETDATE()
from ServerLookup
inner join ImportServers
on ServerLookup.ServerName = ImportServers.ServerName
Where ServerLookup.ServerName = ''