Parse for multiple occurences of something in query string used

Question

HI
A varchar is passed as an input to a stored proc. This could have zero, one or more occurances of a word (e.g. from_no). This will be in form of a name value pair and could occur multiple times. Exampe
query_string = ' abc=123 and from_no > 1 and from_no < 10 and def = 1'
Now I need to parse this string to get the operator and values for the 2 occurences of from_no. How can I do that? How can I go about writing a smple func or sp to parse and return both from_no's?

Answer 1

Perhaps this sample code can help:
with yourtable as
(select ' abc=123 and from_no > 1 and from_no < 10 and def = 1' query_string from dual union all
select ' abc=123 and from_no = 2 and from_no != 30 and def = 1 and from_no=40' query_string from dual)
select  query_string,
        x.n no,
        regexp_substr(query_string,'from_no *[<>!=]* *[0-9]*',1,x.n) exp,       
        regexp_replace(regexp_substr(query_string,'from_no *[<!>=]* *[0-9]*',1,x.n),'.*from_no *([<!>=]*) *([0-9]*).*','\1') op,
        regexp_replace(regexp_substr(query_string,'from_no *[<!>=]* *[0-9]*',1,x.n),'.*from_no *([<!>=]*) *([0-9]*).*','\2') val
from yourtable,
     (select rownum n from dual connect by rownum<=100) x
where regexp_instr(query_string,'from_no',1,x.n)>0   --  end searching in query string when there are no more expressions
order by query_string, x.nI added one more example.
It works with your example, but you will have to adapt the code for your real environment.
This code supports only the operators: =, !=, <, >
This code supports only numeric values without decimal-point.
Edited by: hm on 19.10.2010 22:46