Detect Null Values
Functions isNull or hasNull detect NULL values. isNull
returns a scalar or a vector depending on the input data; hasNull
always returns 0 or 1 indicating if an object contains at least one NULL value.
$ isNull(00i);
1
$ isNull(-128c);
1
// the minimum char is reserved for NULL value
$ isNull(1 NULL 2);
[0,1,0]
$ hasNull(1 NULL 2);
1