Cindy <ctmoore@uci.edu> writes:
> I've a question about escaping special characters in a ~ string operation.
> To match the literal ? I would have thought I could put in \?
> but this seems not to work.
You need to double the backslash to get it through the string-literal
parser. Try
... citation ~ 'y"335\\?"z[0-9]+';
regards, tom lane