Mismatched input error in simple antlr4 grammar

Question

I\'m trying to parse a simple subset of SQL using antlr4.

My grammar looks like this:

grammar Query;
query : select;
select : \'select\' colname (\',         


        

Answer 1

You cannot have two lexer rules that match the same (at least, not in the same mode/state...):

...
COLNAME: [a-z]+ ;
TABLENAME : [a-z]+;
...

Do this instead:

grammar Query;
query     : select;
select    : 'select' colname (',' colname)* 'from' tablename;
colname   : ID;
tablename : ID;
ID        : [a-z]+;
WS        : [ \t\n\r]+ -> skip;