Unexpected syntax error: Unknown column 'ref_0.c1' in 'where clause'

## Bug Report

### 1. Minimal reproduce step (Required)
```sql
create table t1 (c1 text);

-- good
select case when (EXISTS (select 1))
then count(*) over (partition by 1) else 1 end from t1 as ref_0;
-- good
select case when (EXISTS (select 1 where ref_0.c1))
then 1 else 1 end from t1 as ref_0;
-- bad
select case when (EXISTS (select 1 where ref_0.c1))
then count(*) over (partition by 1) else 1 end from t1 as ref_0;
```

### 2. What did you expect to see? (Required)
empty set.

### 3. What did you see instead (Required)
```
ERROR 1054 (42S22): Unknown column 'ref_0.c1' in 'where clause'
```

### 4. What is your TiDB version? (Required)
```
Release Version: v8.5.0-alpha-184-g1c059a1216
Edition: Community
Git Commit Hash: 1c059a1216db711e2cb56ea9f3d1ad8c23db6327
Git Branch: HEAD
UTC Build Time: 2024-11-21 04:56:22
GoVersion: go1.23.3
Race Enabled: false
Check Table Before Drop: false
Store: tikv
```