*Description:*
By pgsql 8.4 I have the following bug:
If the haystack array is null (for example by empty result of array_agg) by
is contained by, and you use it with negation, the the result is false
instead of true.
*Reproduce:*
The following query returns nothing, but it should return 1.
*SELECT 1 FROM NOT(ARRAY[1] <@ NULL**); *
*Workaround:*
*SELECT 1 FROM (haystack IS NULL OR NOT(ARRAY[1] <@ **haystack**)); *