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Databend is supported by SQLancer — the main repository ships a testing implementation for it. SQLancer is credited with 18 bugs in it, reported between 2022-08-29 and 2026-08-25. Its source is at datafuselabs/databend.

A further 1 report was filed and rejected by the developers as invalid or duplicate. Those are kept in the dataset for transparency and are excluded from every count here.

How the project uses SQLancer

Official testing

The Databend project maintains its own SQLancer fork, last updated 2022-09-28.

datafuse-extras/sqlancer is a fork of sqlancer/sqlancer under the Databend project's own GitHub organisation.
/github.com/datafuse-extras/sqlancer last verified 2026-09-06

How the bugs break down

By year reported

2022
4
2023
1
2024
5
2026
8

Who found them

Found by the SQLancer project
7
Found by someone outside the project
11

By status

Fixed
15
Open
3

By symptom

Unclassified
18

By technique

Technique not recorded
17
Ternary Logic Partitioning (TLP)
1

Why each bug counts

The reproducer carries SQLancer's generated schema
9
The report names SQLancer
9

Who reported them (5)

Manuel-Neuer1
6
hanyisong
5
Ming Wei Tan
3
malwaregarry
2
mrigger
2

Every bug on record (19)

One row per report, newest first, each linking to the report itself. Rejected reports are marked and are not part of any count above.

Reported Report Status Technique Reporter
2026-08-25 bug: `HAVING (AGG(col) = AGG(col))` keeps groups whose aggregate is NULL — the same self-comparison in a pr... open — Manuel-Neuer1
2026-08-25 bug: Correlated EXISTS relocated into a projection fails decorrelation with `Internal error 1001: Invalid s... fixed — Manuel-Neuer1
2026-08-24 bug: correlated `EXISTS` with cross-type join keys (`INT = DECIMAL`) wrongly matches NULL probe keys — and ... open — Manuel-Neuer1
2026-08-21 bug: LIKE with an empty-string pattern from a column reference matches any subject fixed — Manuel-Neuer1
2026-08-21 bug: EXISTS correlated subquery treats NULL probe key as the type's default value in LEFT SEMI hash join fixed — Manuel-Neuer1
2026-08-21 bug: CAST(FLOAT AS VARCHAR) returns different strings for the same value depending on whether EXISTS is in ... fixed — Manuel-Neuer1
2026-04-26 bug: SUM(constant) over cross join inside UNION ALL panics with Decimal precision mismatch (regression afte... fixed TLP mrigger
2026-04-17 bug: SELECT AVG(constant) over cross join panics with Decimal precision mismatch fixed — mrigger
2024-06-23 bug: Overflow / divide by zero exceptions not detected in where clause fixed — malwaregarry
2024-06-23 Mismatch between SUM and AVERAGE due to optimisation fixed — Ming Wei Tan
2024-05-18 bug: WHERE clause not working as expected with null column values and string functions (`like`, `in`, etc) fixed — malwaregarry
2024-05-18 `FALSE AND exp1 OR exp1` in WHERE clause results in Lost connection from server fixed — Ming Wei Tan
2024-05-18 WHERE clause not working as expected with NOT fixed — Ming Wei Tan
2024-05-18 Decimal overflow conversion error unknown — Ming Wei Tan
2023-01-31 bug: Connection error using mysql-connector-java:8.0.30 open — hanyisong
2022-12-11 bug: The logic bug obtained by sqlancer fixed — hanyisong
2022-11-29 bug: index out of bounds fixed — hanyisong
2022-09-06 bug: cannot convert NULL to a non-nullable type fixed — hanyisong
2022-08-29 sqlancer: expression expansion error fixed — hanyisong

Every figure on this page is computed from _data/impact/. The attribution policy explains what has to be true for a bug to be counted.