Date: 07/26/06 (Code WTF)    Keywords: no keywords

if (RoleId > 0)
{
RoleJoin = "";
}
else
{
RoleJoin = "--";
}

query = "select *
from blablabla
" + RoleJoin + "INNER JOIN sometable ON (someJoinCondition AND RoleId in (" + RoleId + "))";

ps украдено тут

Source: http://community.livejournal.com/code_wtf/45008.html