Question

I need to split a string from one table into two columns in another table. There are a few different variety of numbers and rules but no clear delimiter. Can I use combo of SUBSTR and INSTR or do I need to use if-then loops in PL/SQL to satisfy all the rules?

Input Table

5 Kent Street 
3 A lindt Street
2/15 bold Street 
9/34-36 carmen Road
12/5a sandford Street

Result

Number  |Street
--------------------
5       |Kent Street
3A      |lindt Street
2/15    |bold Street
9/34-36 |carmen Road
12/5a   |sandford Street

Answer 1

I wouldn’t do this in pl/sql, it is really unnecessary.

Oracle SQL has REGEXP_SUBSTR, REGEXP_REPLACE, REGEXP_COUNT. You also have IF and CASE expressions you can put in the SELECT clause. Go to the SQL reference, FUNCTIONS section: http://docs.oracle.com/cd/E11882_01/server.112/e26088/functions.htm#i1482196

Your dataset has some interesting variations – letters and fractions in the house/building number. What you don’t have (yet) is street names in multiple parts (e.g. Melnea Cass Boulevard here in Boston) or street names with concatenated/missing (“Broadway”) or unusual (“Cedar Passway”) ‘street’ designators.

Start with sample_data as a refactored query to hold your input data. You’ll probably have a table or view or something instead.

For now we are holding the assumption that each street name has two words. We start by counting them with REGEXP_COUNT. This is the subquery COUNTED_DATA with value WORDS as the count of words. Note I append a space to each line of input, in case there isn’t one at the end of the input row of data, so that the count is correct.

I search for each word as

[^ ]+[ ]+

That is, one or more non-spaces followed by one or more spaces. I don’t want to use zero or more spaces ([ ]*) because that is ambiguous.

Then we use a regular expression to pick out the last two words and the first (words minus 2) words.

Here’s the result:

with sample_data as (
    select '5 Kent Street' as addr from dual
    union all select '3 A lindt Street' as addr from dual
    union all select '2/15 bold Street' as addr from dual
    union all select '9/34-36 carmen Road' as addr from dual
    union all select '12/5a sandford Street' from dual
)
select 
    counted_data.addr as "Original Address",
    substr (regexp_replace (addr || ' ', '(([^ ]+[ ]+){' || (words-2) ||'})([^ ].*)','\1'), 1, 10) as "Number",
    substr (trim (regexp_replace (addr || ' ', '(([^ ]+[ ]+){' || (words-2) ||'})([^ ].*)','\3')), 1, 25) as "Street"
from
(
    select sample_data.addr, regexp_count(addr || ' ', '[ ]+') as words
    from sample_data
) counted_data

Original Address      Number     Street                   
--------------------- ---------- -------------------------
5 Kent Street         5          Kent Street               
3 A lindt Street      3 A        lindt Street              
2/15 bold Street      2/15       bold Street               
9/34-36 carmen Road   9/34-36    carmen Road               
12/5a sandford Street 12/5a      sandford Street           

To make this readable I used ‘substr’ to cut down the length of the output columns. (“COLUMN” doesn’t work in SQL Developer.)