Grouped `BIT` bytes change when consumed by `GROUP_CONCAT` after view materialization.

[123lpygithub]

Under SQL-equivalent rewriting, the source and mutated queries differ only in extracting the grouped BIT(1) subquery into a view. The GROUP_CONCAT(... ORDER BY ...) result changes from ASCII byte 0x31 to raw byte 0x01.

Version: 8.0.44-alisql-dev

How to repeat:

DROP VIEW IF EXISTS v;
DROP TABLE IF EXISTS t;

CREATE TABLE t (
  x BIT(1) NOT NULL
);

INSERT INTO t VALUES (b'1');

-- Original SQL
SELECT GROUP_CONCAT(x ORDER BY x)
FROM (
  SELECT x
  FROM t
  GROUP BY x
) q;

-- View SQL
CREATE VIEW v AS
SELECT x
FROM (
  SELECT x
  FROM t
  GROUP BY x
) q;

-- Mutated SQL
SELECT GROUP_CONCAT(x ORDER BY x)
FROM v;

Observed mismatch:

• original result:

GROUP_CONCAT(x ORDER BY x)
0x31

• mutated result:

GROUP_CONCAT(x ORDER BY x)
0x01