Add support for the LEVEL pseudo-column in the recursive part of
a common table expression.  LEVEL has the value of 1 on the first iteration
and successively larger integer values of subsequent iterations.  It cannot
have a table qualifier.  Actual columns named "level" can still be accessed
by including the table name qualifier.

FossilOrigin-Name: cc1cb3217800ff666a00bf4f544a5a477589bc1b
8 files changed