PostgreSQL, getting min and max date from text column

Question

I have such situation in table:

1   01.02.2011
2   05.01.2011
3   06.03.2012
4   07.08.2011
5   04.03.2013
6   06.08.2011
7   
8   02.02.2013
9   04.06.2010
10           


        

Answer 1

Try something like:

SELECT max(to_date(nullif(mydatetxt,''), 'DD.MM.YYYY')),
       min(to_date(nullif(mydatetxt,''), 'DD.MM.YYYY'))
FROM table_name;

SELECT max(to_date(nullif(mydatetxt,''), 'DD.MM.YYYY')),
       min(to_date(nullif(mydatetxt,''), 'DD.MM.YYYY'))
FROM table_name
WHERE date_part('year',to_date(nullif(mydatetxt,''), 'DD.MM.YYYY')) = 2012;