[SQL] Join columns

[Przemysław Słupkowski]

Hi How can I generate md5 chcecksum for a row in table. I have 47 columns in table and I want to generate chceck sum to check is integrity od data. I want to do something like this   select md5((idTowBK || SKDK || SKDT || SKGR || SKIR || SKKL || SKKR || SKLM || SKNZ || SKOP || SKPR)::varchar)   from FARM_BKam limit 10   and its works :-) But when I increase number of columns higher than 12 then return's null string