Incorrect result returned by UNION ALL (SQLancer-TLP) #11742
Description
Describe the bug
Here is Q1 select nvl(v1, 0.5) from tt;
then let Q1 union a empty set, two queries should have the same result, but it's returning a different result.
Looks like it's an incorrect casting (cast double to int), since double has higher precision, it should cast in the opposite direction
Reproducer in datafusion-cli
DataFusion CLI v40.0.0
> create table tt(v1 int);
0 row(s) fetched.
Elapsed 0.072 seconds.
> insert into tt values (1),(null);
+-------+
| count |
+-------+
| 2 |
+-------+
1 row(s) fetched.
Elapsed 0.051 seconds.
> select nvl(v1, 0.5) from tt;
+-------------------------+
| nvl(tt.v1,Float64(0.5)) |
+-------------------------+
| 1.0 |
| 0.5 |
+-------------------------+
2 row(s) fetched.
Elapsed 0.015 seconds.
> select nvl(v1, 0.5) from tt
union all
select null where false;
+-------------------------+
| nvl(tt.v1,Float64(0.5)) |
+-------------------------+
| 1 |
| 0 |
+-------------------------+
2 row(s) fetched.
Elapsed 0.007 seconds.
// Example: two number have different type, cast to the type with higher precision/range
> select 1 + 0.5;
+-------------------------+
| Int64(1) + Float64(0.5) |
+-------------------------+
| 1.5 |
+-------------------------+
1 row(s) fetched.
Elapsed 0.008 seconds.
To Reproduce
No response
Expected behavior
No response
Additional context
Found by SQLancer #11030