MAPCONTAINSVALUE

Determines whether a VMap contains a specific value. Use this scalar function to return true (t), if the value exists, or false (f), if it does not.

Syntax

MAPCONTAINSVALUE(VMap_data, 'virtual_column_value')

Arguments

VMap_data

Any VMap data. The VMap can exist as:

  • The __raw__ column of a flex table
  • Data returned from a map function such as maplookup()
  • Other database content 
virtual_column_value

The value whose existence you want to confirm.

Examples

This example shows how to use mapcontainsvalue()  to determine whether or not a virtual column contains a particular value. Create a flex table (ftest), and populate it with some virtual columns and values. Name both virtual columns one:  

=> CREATE FLEX TABLE ftest();
CREATE TABLE
=> copy ftest from stdin parser fjsonparser();
Enter data to be copied followed by a newline.
End with a backslash and a period on a line by itself.
>> {"one":1, "two":2}
>> {"one":"one","2":"2"}
>> \.

Call mapcontainsvalue() on the ftest map data. The query returns false (f) for the first virtual column, and true (t) for the second , which contains the value one: 

=> SELECT MAPCONTAINSVALUE(__raw__, 'one') FROM ftest; 
mapcontainsvalue
------------------
f
t
(2 rows)

See Also