fix: deletion of null values

[dantengsky]

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Summary

fixing issue

• Bug: incorrect deletion of null valued rows #6275

by inverse the filter result, instead of the filter expression.

mysql> create table t(c int null);
Query OK, 0 rows affected (0.06 sec)

mysql> insert into t values(1), (2), (NULL);
Query OK, 0 rows affected (0.06 sec)

mysql> delete from t where c=1;
Query OK, 0 rows affected (0.06 sec)

mysql> select * from t;
+------+
| c    |
+------+
|    2 |
| NULL |
+------+
2 rows in set (0.03 sec)
Read 2 rows, 8.00 B in 0.006 sec., 346.05 rows/sec., 1.35 KiB/sec.

mysql> delete from t where c is null;
Query OK, 0 rows affected (0.05 sec)

mysql> select * from t;
+------+
| c    |
+------+
|    2 |
+------+
1 row in set (0.06 sec)
Read 1 rows, 4.00 B in 0.005 sec., 197.37 rows/sec., 789.48 B/sec.

mysql> delete from t where 1=1;
Query OK, 0 rows affected (0.05 sec)

mysql> select * from t;
Query OK, 0 rows affected (0.03 sec)

Changelog

• Bug Fix
• Not for changelog (changelog entry is not required)

Related Issues

Fixes #6275

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1 Ignored Deployment

Name	Status	Preview	Updated
databend	⬜️ Ignored (Inspect)		Jun 28, 2022 at 3:17PM (UTC)

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