T SQL Conditional String Concatenation - sql

Question

Have a 5 columns of address data. I need to concatenate these fields into a single address with spaces in between the values if they exist. If the column has a null value I should skip it and not enter any space.
select
case
when street_number != '' THEN (cast(street_number as int))
end as street_number,
case
when street_ext != '' then
case
when street_ext = 50 then '1/2'
end
end as street_ext,
case
when street_direct ! = '' then street_direct
end as street_direct,
case
when site_street ! = '' then site_street
end as site_street,
case
when site_address ! = '' then site_address
end as site_address
from parcel
what I'd like to do is have a variable and assign it to the value of the first column street_number, then when I move on to the next column, street_ext, if it isn't null I'd like to check to see if the variable is null and if not, append a space and the value...and so on down the road.
I'm rusty as hell and could use a push in the right direction.
Thanks everyone.

Answer 1

Use the "+" to concatenate strings in TSQL:
SELECT CASE
WHEN LEN(p.street_number) > 0 THEN p.street_number + ' '
ELSE ''
END +
CASE
WHEN p.street_ext = 50 THEN '1/2'
WHEN LEN(p.street_ext) > 0 THEN ''
ELSE p.street_ext
END + ' ' +
CASE
WHEN LEN(p.street_direct) > 0 THEN p.street_direct + ' '
ELSE ''
END +
CASE
WHEN LEN(p.site_street) > 0 THEN p.site_street + ' '
ELSE ''
END +
CASE
WHEN LEN(p.site_address) > 0 THEN p.site_address + ' '
ELSE ''
END AS full_address
FROM PARCEL p
The LEN function returns zero if the string value is NULL, or a zero length string.

Answer 2

Nested isnulls could do what you need. Something like:
SELECT
ISNULL(streetnumber + ' ', '')
+ ISNULL(streetext + ' ', '')
etc
relying on the fact that NULL + ' ' = NULL.

Answer 3

Something along the lines of:
select coalesce(street_number+' ','')+
coalesce(case when street_ext=50 then '1/2' else null end+' ','')+
coalesce(street_direct+' ','')+
coalesce(site_street+' ','')+
coalesce(site_address,'')
from parcel

Answer 4

I have assumed your data types are all varchar or similar for simplicity. If you are OK with removing any double spaces, how about:
rtrim(ltrim(replace(isnull(street_number) + ' '
+ isnull(street_ext) + ' '
+ isnull(street_direct) + ' '
+ isnull(site_street) + ' '
+ isnull(site_address), ' ', ' ')))

Answer 5

First I would declare the seperator as a variable, because customers are notorious for changing these.
I would do this as follows:
DECLARE #AddressSeperator NVARCHAR(5) = ' '
...and then for the column declation, I'd use the following:
, CONCAT
(
(CASE WHEN LEN(p.street_number) > 0 THEN p.street_number + #AddressSeperator ELSE '' END)
, (CASE WHEN p.street_ext = 50 THEN '1/2' + #AddressSeperator WHEN LEN(p.street_ext) > 0 THEN p.street_ext + #AddressSeperator ELSE '' END)
, (CASE WHEN LEN(p.street_direct) > 0 THEN p.street_direct + #AddressSeperator ELSE '' END)
, (CASE WHEN LEN(p.site_street) > 0 THEN p.site_street + #AddressSeperator ELSE '' END)
, ISNULL(p.site_address, '')
) AS [full_address]