"AND" -?[0-9]+ "WHERE" ">=" "=" "<=" ">" "!=" "<" "SELECT" "FROM" "[a-zA-Z]" "," "[ \t\n]" . SELECT columns FROM tables WHERE whereExpression COMMA column ID COMMA table ID primaryExpression whereExpression AND primaryExpression filterExpression joinExpression INT binop column column binop INT EQ NE LT LE GT GE