How to use

org.h2.expression.ExpressionColumn

constructor

private LocalResult createResult() {
  Expression[] expressions = { new ExpressionColumn(
      session.getDatabase(), new Column("SCRIPT", Value.STRING)) };
  return new LocalResult(session, expressions, 1);
}

Column column = new Column("PLAN", Value.STRING);
Database db = session.getDatabase();
ExpressionColumn expr = new ExpressionColumn(db, column);
Expression[] expressions = { expr };
result = new LocalResult(session, expressions, 1);

/**
 * Extracts expression columns from the given result set.
 *
 * @param session the session
 * @param rs the result set
 * @return an array of expression columns
 */
public static Expression[] getExpressionColumns(Session session, ResultSet rs) {
  try {
    ResultSetMetaData meta = rs.getMetaData();
    int columnCount = meta.getColumnCount();
    Expression[] expressions = new Expression[columnCount];
    Database db = session == null ? null : session.getDatabase();
    for (int i = 0; i < columnCount; i++) {
      String name = meta.getColumnLabel(i + 1);
      int type = DataType.getValueTypeFromResultSet(meta, i + 1);
      int precision = meta.getPrecision(i + 1);
      int scale = meta.getScale(i + 1);
      int displaySize = meta.getColumnDisplaySize(i + 1);
      Column col = new Column(name, type, precision, scale, displaySize);
      Expression expr = new ExpressionColumn(db, col);
      expressions[i] = expr;
    }
    return expressions;
  } catch (SQLException e) {
    throw DbException.convert(e);
  }
}

expressionColumns = new ArrayList<>(allColumns.size());
for (Column column : allColumns) {
  expressionColumns.add(new ExpressionColumn(db, column));
    if (idx >= 1 && idx <= cnt) {
      Column column = columns[idx - 1];
      expressionColumns.add(new ExpressionColumn(db, column));
      allColumns.add(column);
    expressionColumns.add(new ExpressionColumn(db, column));
    allColumns.add(column);

@Override
public Expression[] getExpressionColumns(Session session) {
  ExpressionColumn[] expr = new ExpressionColumn[list.length];
  for (int i = 0; i < list.length; i++) {
    Expression e = list[i];
    Column col = new Column("C" + (i + 1),
        e.getType(), e.getPrecision(), e.getScale(),
        e.getDisplaySize());
    expr[i] = new ExpressionColumn(session.getDatabase(), col);
  }
  return expr;
}

private int expandColumnList(TableFilter filter, int index) {
  Table t = filter.getTable();
  String alias = filter.getTableAlias();
  Column[] columns = t.getColumns();
  for (Column c : columns) {
    if (!c.getVisible()) {
      continue;
    }
    if (filter.isNaturalJoinColumn(c)) {
      continue;
    }
    String name = filter.getDerivedColumnName(c);
    ExpressionColumn ec = new ExpressionColumn(
        session.getDatabase(), null, alias, name != null ? name : c.getName());
    expressions.add(index++, ec);
  }
  return index;
}

/**
 * Extracts expression columns from ValueArray
 *
 * @param session the current session
 * @param value the value to extract columns from
 * @return array of expression columns
 */
static Expression[] getExpressionColumns(Session session, ValueArray value) {
  Value[] list = value.getList();
  ExpressionColumn[] expr = new ExpressionColumn[list.length];
  for (int i = 0, len = list.length; i < len; i++) {
    Value v = list[i];
    Column col = new Column("C" + (i + 1), v.getType(),
        v.getPrecision(), v.getScale(),
        v.getDisplaySize());
    expr[i] = new ExpressionColumn(session.getDatabase(), col);
  }
  return expr;
}

String columnName = columnNamer.getColumnName(l,i,l.getAlias());
Column col = new Column(columnName, type, prec, scale, displaySize);
Expression e = new ExpressionColumn(session.getDatabase(), col);
expressions.add(e);

    return new ExpressionColumn(database, schema, objectName, name);
  return new ExpressionColumn(database, schema, objectName, name);
return new ExpressionColumn(database, null, objectName, name);

Expression condition = null;
for (Column column : indexedColumns) {
  ExpressionColumn expr = new ExpressionColumn(session.getDatabase(),
      table.getSchema().getName(), table.getName(),
      column.getName());

for (int i = 0; i < len; i++) {
  Column c = columnList[i];
  ExpressionColumn col = new ExpressionColumn(db, c);
  header[i] = col;

if (equalsToken(tableColumnName, joinColumnName)) {
  join.addNaturalJoinColumn(c);
  Expression tableExpr = new ExpressionColumn(
      database, tableSchema,
      last.getTableAlias(), tableColumnName);
  Expression joinExpr = new ExpressionColumn(
      database, joinSchema, join.getTableAlias(),
      joinColumnName);

  r = readTermObjectDot(name);
} else {
  r = new ExpressionColumn(database, null, null, name);
    r = readFunctionWithoutParameters("CURRENT_DATE");
  } else {
    r = new ExpressionColumn(database, null, null, name);
      throw getSyntaxError();
    r = new ExpressionColumn(database, null, null, name);
  } else {
    String time = currentValue.getString();
        throw getSyntaxError();
      r = new ExpressionColumn(database, null, null, name);
    } else {
      String timestamp = currentValue.getString();
    r = ValueExpression.get(ValueString.get(text));
  } else {
    r = new ExpressionColumn(database, null, null, name);
  r = new ExpressionColumn(database, null, null, name);

private LocalResult createResult() {
  Expression[] expressions = { new ExpressionColumn(
      session.getDatabase(), new Column("SCRIPT", Value.STRING)) };
  return new LocalResult(session, expressions, 1);
}

private LocalResult createResult() {
  Expression[] expressions = { new ExpressionColumn(
      session.getDatabase(), new Column("SCRIPT", Value.STRING)) };
  return new LocalResult(session, expressions, 1);
}

private int expandColumnList(TableFilter filter, int index) {
  Table t = filter.getTable();
  String alias = filter.getTableAlias();
  Column[] columns = t.getColumns();
  for (Column c : columns) {
    if (filter.isNaturalJoinColumn(c)) {
      continue;
    }
    ExpressionColumn ec = new ExpressionColumn(
        session.getDatabase(), null, alias, c.getName());
    expressions.add(index++, ec);
  }
  return index;
}

private LocalResult createResult() {
  ObjectArray cols = new ObjectArray();
  cols.add(new ExpressionColumn(session.getDatabase(), new Column("SCRIPT", Value.STRING)));
  return new LocalResult(session, cols, 1);
}

@Override
public Expression[] getExpressionColumns(Session session) {
  ExpressionColumn[] expr = new ExpressionColumn[list.length];
  for (int i = 0; i < list.length; i++) {
    Expression e = list[i];
    Column col = new Column("C" + (i + 1),
        e.getType(), e.getPrecision(), e.getScale(),
        e.getDisplaySize());
    expr[i] = new ExpressionColumn(session.getDatabase(), col);
  }
  return expr;
}

@Override
public Expression[] getExpressionColumns(Session session) {
  ExpressionColumn[] expr = new ExpressionColumn[list.length];
  for (int i = 0; i < list.length; i++) {
    Expression e = list[i];
    Column col = new Column("C" + (i + 1),
        e.getType(), e.getPrecision(), e.getScale(),
        e.getDisplaySize());
    expr[i] = new ExpressionColumn(session.getDatabase(), col);
  }
  return expr;
}

public LocalResult query(int maxrows) throws SQLException {
  // TODO rights: are rights required for explain?
  ObjectArray expressions = new ObjectArray();
  Column column = new Column("PLAN", Value.STRING);
  ExpressionColumn expr = new ExpressionColumn(session.getDatabase(), column);
  expressions.add(expr);
  result = new LocalResult(session, expressions, 1);
  if (maxrows >= 0) {
    String plan = command.getPlanSQL();
    add(plan);
  }
  result.done();
  return result;
}