void appendInsertClause(StringBuilder sb) {
        sb.append("INSERT INTO ");
        dialect.quoteIdentifier(sb, jdbcTable.getExternalNameList());
        sb.append(' ');
        appendFieldNames(sb, jdbcTable.dbFieldNames());
    }
@Test
    void testAppendInsertClause() {
        PostgresUpsertQueryBuilder builder = new PostgresUpsertQueryBuilder(jdbcTable, dialect);
        StringBuilder sb = new StringBuilder();
        builder.appendInsertClause(sb);

        String insertClause = sb.toString();
        assertThat(insertClause).isEqualTo("INSERT INTO \"table1\" (\"field1\",\"field2\")");
    }