is null

is null operator is used to test for NULL values, which is equivalent to the function isNull.

is not null operator is used to test for non-empty values (NOT NULL values).

The SQL keywords is null/is not null support distributed queries to access data from DFS tables.

Examples

$ t= table(`a1`a2`a3`b1`b2`b3`c1`c2 as id, 7 4 NULL 1 8 NULL 12 NULL as val)
$ select id from t where val is null
// equivalent to `select id from t where isNull(val)`

id
a3
b3
c2

$ select id from t where  val  is not null
// equivalent to `select id from t where not isNull(val)`

id
a1
a2
b1
b2
c1