Bug #121644 Incorrect ERROR 1054 for a qualified GROUP BY column referenced in HAVING

Description:
MySQL Community Server 9.7.1 rejects a valid grouped SELECT with `ERROR 1054: Unknown column 'a.c2' in 'having clause'`. The column exists and is explicitly included in `GROUP BY`. Both input tables expose a column named `c2`, and both qualified columns appear in `GROUP BY`, but `a.c2` is not projected by SELECT.

The reduced reproduction uses two single-column temporary tables and three rows. It requires no indexes, window functions, correlated subqueries, or persistent data changes. The error also occurs with `EXPLAIN` and after disabling `ONLY_FULL_GROUP_BY`. Adding `a.c2` to SELECT or giving that input column a distinct name makes the query succeed.

This is an incorrect rejection of a valid query: a grouping column may be referenced in HAVING without appearing in SELECT, and the qualifier `a` identifies the intended input column. The observations point to a HAVING name-resolution defect; the internal implementation cause has not been established.

## Expected behaviour

The join produces `(a.c2, b.c2) = (-1, 10)` and `(1, 10)`. Grouping by both columns creates two groups. HAVING retains only the group with `a.c2 = 1`, so the result should be:

```text
+----+---+
| c2 | n |
+----+---+
| 10 | 1 |
+----+---+
```

Both grouping columns are qualified, and the only nonaggregate SELECT expression, `b.c2`, is explicitly grouped. The query satisfies `ONLY_FULL_GROUP_BY`.

## Actual behaviour

```text
ERROR 1054 (42S22): Unknown column 'a.c2' in 'having clause'
```

PyMySQL reports:

```text
OperationalError(1054, "Unknown column 'a.c2' in 'having clause'")
```

The same error occurs when `EXPLAIN` is prepended to the SELECT.

How to repeat:
CREATE TEMPORARY TABLE valscope_having_a (c2 INT NOT NULL);
CREATE TEMPORARY TABLE valscope_having_b (c2 INT NOT NULL);

INSERT INTO valscope_having_a VALUES (-1), (1);
INSERT INTO valscope_having_b VALUES (10);

SELECT b.c2, COUNT(*) AS n
FROM valscope_having_a AS a
JOIN valscope_having_b AS b ON TRUE
GROUP BY b.c2, a.c2
HAVING a.c2 > 0;