EMPTYMAP

Constructs a new VMap with one row but without keys or data. Use this transform function to populate a map without using a flex parser. Instead, you use either from SQL queries or from map data present elsewhere in the database.

Syntax

EMPTYMAP()

Arguments

None

Examples

Create an Empty Map 

=> SELECT EMPTYMAP();
                             emptymap
------------------------------------------------------------------
 \001\000\000\000\004\000\000\000\000\000\000\000\000\000\000\000
(1 row)

Create an Empty Map from an Existing Flex Table

If you create an empty map from an existing flex table, the new map has the same number of rows as the table from which it was created.

This example shows the result if you create an empty map from the darkdata table, which has 12 rows of JSON data:

=> SELECT EMPTYMAP() FROM darkdata;
                             emptymap
------------------------------------------------------------------
 \001\000\000\000\004\000\000\000\000\000\000\000\000\000\000\000
 \001\000\000\000\004\000\000\000\000\000\000\000\000\000\000\000
 \001\000\000\000\004\000\000\000\000\000\000\000\000\000\000\000
 \001\000\000\000\004\000\000\000\000\000\000\000\000\000\000\000
 \001\000\000\000\004\000\000\000\000\000\000\000\000\000\000\000
 \001\000\000\000\004\000\000\000\000\000\000\000\000\000\000\000
 \001\000\000\000\004\000\000\000\000\000\000\000\000\000\000\000
 \001\000\000\000\004\000\000\000\000\000\000\000\000\000\000\000
 \001\000\000\000\004\000\000\000\000\000\000\000\000\000\000\000
 \001\000\000\000\004\000\000\000\000\000\000\000\000\000\000\000
 \001\000\000\000\004\000\000\000\000\000\000\000\000\000\000\000
 \001\000\000\000\004\000\000\000\000\000\000\000\000\000\000\000
(12 rows)

See Also