Extract specific token out of ANTLR Parse Tree

i'm trying to extract data from the ANTLR parse tree, but not fully grasping how this should be done correctly

Let's say i have the following two SQL queries:

		// language=SQL
		val sql3 = """
		CREATE TABLE session(
			id           uuid                    not null
				constraint account_pk
					primary key,
			created 	timestamp	default now() not null
		)
		""".trimIndent()

		// language=SQL
		val sql4 = """
			CREATE TABLE IF NOT EXISTS blah(
				id           uuid                    not null
				constraint account_pk
					primary key,
				created 	timestamp	default now() not null
			)
		""".trimIndent()

Now i parse both of them:

		val visitor = Visitor()
		listOf(sql3, sql4).forEach { sql ->
			val lexer = SQLLexer(CharStreams.fromString(sql))
			val parser = SQLParser(CommonTokenStream(lexer))

			visitor.visit(parser.sql())
			println(visitor.tableName)

		}

In my visitor if i visit the tableCreateStatement, i get the parse tree, but obviously just grabbing child1 will work for sql3, but not for sql4 since child1 in sql4 is IF NOT EXISTS

class Visitor : SQLParserBaseVisitor<Unit>() {

	var tableName = ""

	override fun visitCreate_table_statement(ctx: SQLParser.Create_table_statementContext?) {
		tableName = ctx?.getChild(1)?.text ?: ""
		super.visitCreate_table_statement(ctx)
	}

}

Is there a way to find a specific token in the parse tree?

I'm assuming the payload has something to do with it, but since it's of type Any, i'm not sure what to check it against

	override fun visitCreate_table_statement(ctx: SQLParser.Create_table_statementContext?) {
		ctx?.children?.forEach {
			if (it.payload.javaClass == SQLParser::Schema_qualified_nameContext) {
				tableName = it.text
			}
		}
		super.visitCreate_table_statement(ctx)
	}

EDIT: the .g4 files are from
https://github.com/pgcodekeeper/pgcodekeeper/tree/master/apgdiff/antlr-src

this seems to work

	override fun visitCreate_table_statement(ctx: SQLParser.Create_table_statementContext?) {
		ctx?.children?.forEach {
			if (it.payload.javaClass == Schema_qualified_nameContext::class.java) {
				tableName = it.text
			}
		}
		super.visitCreate_table_statement(ctx)
	}

For branching trees

	fun walkLeaves(
		childTree: ParseTree = internalTree,
		leave: (childTree: ParseTree) -> Unit) {

		if (childTree.childCount == 0) {
			if (!childTree.text?.trim().isNullOrBlank()) {
				leave(childTree)
			}
		} else {
			for (i in 0 until childTree.childCount) {
				walkLeaves(childTree = childTree.getChild(i), leave = leave)
			}
		}
	}

fun extractSQL(
	childTree: ParseTree,
	tokens: MutableList<String> = mutableListOf()
): String {

	walkLeaves(childTree = childTree) { leave ->
		tokens.add(leave.text)
	}

    ...

}