Question

I have the following sample data for a particular column symbol for sample table.

(Update:) The data is not in a regular pattern. Number may occur at any place in between characters.

symbol

COL4A1
COL4A3
COL8A2
COL2A1
COL12A1
COL12A1
COL16A1
COL19A1

I need to sort the this data on database level. I used the following query:

select symbol from sample order by symbol asc

Result is follows:

COL12A1
COL12A1
COL16A1
COL19A1
COL2A1
COL4A1
COL4A3
COL8A2

But I need to get the order in the following way:

COL2A1
COL4A1
COL4A3
COL8A2
COL12A1
COL12A1
COL16A1
COL19A1

Answer 1

PostgreSQL doesn’t offer a number-aware collation that can do “humanized” sorts like “1A, 2A, 3A, … 10A, 11A, …”. It relies on the operating system for collation, and I’m not aware of any OS that exposes such a collation to applications.

To do this, you need to split the text according to a pattern and order by the pattern parts, probably using regexp_matches.

CREATE TABLE Table1 ("symbol" text);
INSERT INTO Table1 ("symbol") VALUES
    ('COL4A1'),('COL4A3'),('COL8A2'),('COL2A1'),
    ('COL12A1'),('COL12A1'),('COL16A1'),('COL19A1');

WITH matched(symbol, symbol_parts) AS (
  SELECT symbol, regexp_matches(symbol, '(\D*)(\d+)(\D+)(\d+)')
  FROM Table1
)
SELECT symbol 
FROM matched
ORDER BY symbol_parts[1], symbol_parts[2]::integer,
         symbol_parts[3], symbol_parts[4]::integer;