Failed to autoconvert '1' to text.

[Szymon Guz <mabewlun@xxxxxxxxx>]

Hi,

why isn't 'aa' always treated as string?

While testing function for levenshtein distance I've noticed that:

with x as (

  select 

  '1' a,

  '2' b

)

SELECT levenshtein(a, b), length(a)

FROM x;

ERROR:  failed to find conversion function from unknown to text

with x as (

  select 

  '1'::TEXT a,

  '2'::TEXT b

)

SELECT levenshtein(a, b), length(a)

FROM x;

 levenshtein | length 

-------------+--------

           1 |      1

(1 row)

Why should I cast '1' to '1'::TEXT to satisfy a function (TEXT, TEXT)?

thanks,

Szymon