[antlr-interest] how to distinguish "::" from ":"

[=?gb2312?q?=CB=EF=BC=CD=B8=D5=20Jigang=20(Robert)=20Sun?=]

The following rules only match single_column instead of double_column when meet input "::",

check:single_column|double_column;
double_column:"::" ;
single_column:":";

what I know is that by default antlr lexer is greedy, it is not hungary this moment.

Jigang   

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