SqlNode fromClause = new SqlIdentifier(
ImmutableList.of("INFORMATION_SCHEMA", "COLUMNS"), null, SqlParserPos.ZERO, null);
final SqlIdentifier table = node.getTable();
final SchemaPlus schema = findSchema(context.getRootSchema(), context.getNewDefaultSchema(),
Util.skipLast(table.names));
final String tableName = Util.last(table.names);
if (schema.getTable(tableName) == null) {
throw new RelConversionException(String.format("Table %s is not valid", Util.sepList(table.names, ".")));
}
SqlNode schemaCondition = null;
if (!isRootSchema(schema)) {