Extract Value from a string PostgreSQL

Question

Simple Question

I have the following type of results in a string field

'Number=123456'
'Number=1234567'
'Number=12345678'

How do I extract the value from the string with regard that the value can change between 5-8 figures

So far I did this but I doubt that fits my requirement

SELECT substring('Size' from 8 for ....

If I can tell it to start from the = sign till the end that would help!

Answer 1

The likely simplest solution is to trim 7 leading characters with right():

right(str, -7)

Demo:

SELECT str, right(str, -7)
FROM (
   VALUES ('Number=123456')
        , ('Number=1234567')
        , ('Number=12345678')
   ) t(str);

       str       |  right
-----------------+----------
 Number=123456   | 123456
 Number=1234567  | 1234567
 Number=12345678 | 12345678

Answer 2

You could use REPLACE:

SELECT col, REPLACE(col, 'Number=', '')
FROM tab;

DBFiddle Demo

Answer 3

Based on this question: Split comma separated column data into additional columns

You could probably do the following:

SELECT *, split_part(col, '=', 2)
FROM table;

Answer 4

You may use regexp_matches :

with t(str) as
(
 select 'Number=123456'   union all 
 select 'Number=1234567'  union all
 select 'Number=12345678' union all
 select 'Number=12345678x9' 
)
select t.str  as "String", 
       regexp_matches(t.str, '=([A-Za-z0-9]+)', 'g')  as "Number"
  from t;

String            Number
--------------    ---------
Number=123456     123456
Number=1234567    1234567
Number=12345678   12345678
Number=12345678x9 12345678x9 
--> the last line shows only we look chars after equal sign even if non-digit

Rextester Demo