How to concatenate the "overflow" of fields with character limits - sql

Question

I have a table with 3 address fields and each address field has a limit of 100 characters each.
I need to create a query to make the maximum character limit for each address field to be 30 characters long. If one address field is > 30 then I'll cut off the rest, but take the remainder and concatenate it onto the beginning of the next address field. I would do this until the last address field (address3) is filled up and then just get rid of the remainder on the last address field.
Is there a way to do this with an SQL query or with T-SQL?

Answer 1

You don't specify what to do with very short addresses, but my first crack at it would be something like this:
with temp as
(
select 1 id, 'abcdefghijklmnopqrstuvwxyz123456789' part1, 'second part' part2, 'third part' part3
),
concated as
(
SELECT id, part1 + part2 + part3 as whole
FROM temp
)
select id,
SUBSTRING(whole, 0, 30) f,
SUBSTRING(whole, 30,30) s,
SUBSTRING(whole, 60,30) t
from concated
This returns:
id | f | s | t
1 | abcdefghijklmnopqrstuvwxyz123 | 456789second partthird part |
If that's not what you're looking for please specify the desired output for the above.
UPDATE:
Well... this appears to work but it's pretty gross. I'm sure someone can come up with a better solution.
with temp as
(
select 1 id, 'abcdefghijklmnopqrstuvwxyz123456789 ' part1, 'second part' part2, 'third part' part3
)
select id,
SUBSTRING(part1, 0, 30) f,
SUBSTRING(SUBSTRING(part1, 30, 70) + SUBSTRING(part2, 0,30),0,30) s,
SUBSTRING(SUBSTRING(SUBSTRING(SUBSTRING(part1, 30, 70) + SUBSTRING(part2, 0,30),30,70),0,30) + SUBSTRING(part3, 0,30),0,30) t
from temp

Answer 2

I think I'd go with the problem description, and write something that's "obviously" correct (provided I've understood your spec :-))
/* Setup data - second example stolen from Abe, first just showing that it works with short enough data */
declare #t table (ID int not null,Address1 varchar(100) not null,Address2 varchar(100) not null,Address3 varchar(100) not null)
insert into #t (ID,Address1,Address2,Address3)
values (1,'abc','def','ghi'),
(2,'abcdefghijklmnopqrstuvwxyz123456789 ', 'second part', 'third part')
/* Actual query - shift address pieces through the address fields, but only to later ones */
;with Shift1 as (
select
ID,SUBSTRING(Address1,1,30) as Address1,SUBSTRING(Address1,31,70) as Address1Over,Address2,Address3
from #t
), Shift2 as (
select
ID,Address1,SUBSTRING(Address1Over+Address2,1,30) as Address2,SUBSTRING(Address1Over+Address2,31,70) as Address2Over,Address3
from Shift1
), Shift3 as (
select
ID,Address1,Address2,SUBSTRING(Address2Over+Address3,1,30) as Address3
from Shift2
)
select * from Shift3
Result:
ID Address1 Address2 Address3
----------- ------------------------------ ------------------------------ ------------------------------
1 abc def ghi
2 abcdefghijklmnopqrstuvwxyz1234 56789 second part third part