SQLSubselect — Property Get returns wrong variable

SQLSubselect: SelectAs getter returns wrong variable
- Component: `src/ClassModules/SQLSubselect.cls` (around 0–39)

### Problem
- Getter returns an undefined identifier instead of the backing field.

### Snippet (actual)
```vb
Property Get SelectAs() As String
SelectAs = aAs
End Property
```

### Expected
```vb
Property Get SelectAs() As String
SelectAs = sAs
End Property
```

### Steps to Reproduce
1) Read `SelectAs` from an instance.

### Actual
- Returns empty/undefined; potential compile/runtime error.

### Proposed Fix
- Return `sAs`.

---

Open src/ClassModules/SQLSubselect.cls and inspect the SelectAs property getter around lines 0–39, comparing it with the backing fields used by the class. Verify that reading SelectAs from an instance returns the stored alias value without an empty result or compile/runtime error.

Written by the indexing model from the issue text.