public List<String> build() {
    switch (dialect.getId()) {
      case PostgreSql.ID:
        StringBuilder sql = new StringBuilder().append(ALTER_TABLE).append(tableName).append(" ");
        dropColumns(sql, "DROP COLUMN ", columns);
        return Collections.singletonList(sql.toString());
      case MsSql.ID:
        return Collections.singletonList(getMsSQLStatement(columns));
      case Oracle.ID:
        return Collections.singletonList(getOracleStatement());
      case H2.ID:
        return Arrays.stream(columns).map(this::getMsSQLStatement).toList();
      default:
        throw new IllegalStateException(String.format("Unsupported database '%s'", dialect.getId()));
    }
  }
@Test
  public void drop_columns_on_oracle() {
    assertThat(new DropColumnsBuilder(new Oracle(), "issues", "date_in_ms", "name").build())
      .containsOnly("ALTER TABLE issues SET UNUSED (date_in_ms, name)");
  }