For array types, the validity of an assignment to an SQL
array variable or parameter is determined according to the following
rules:
- If the right hand side of the assignment is an SQL array variable
or parameter, the TRIM_ARRAY function, or a CAST expression, then
its type must be compatible with the SQL array variable or parameter
on the left hand side of the assignment.
- If the right hand side of the assignment is an array constructor
or the ARRAY_AGG function, then it is implicitly cast to the type
of the SQL array variable or parameter on the left hand
side.