CODEWITHSUNDEEP
mysqlsqlmariadb
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Sodved

Reputation: 8588

mariadb/mysql Nested `WITH` statement causes table-not-found error

I am not sure if this is a documented limit in mariadb or a bug in its query parsing. We are porting some enormous queries from vertica to mariadb, and I have encountered cases where queries with nested WITH clauses is throwing a bogus table-not-found error.

Running mariadb version: 10.3.14

The actual sql is monstrous, but I have been able to reduce it to a simple case which fails. with-bad.sql

WITH v1 AS
(   SELECT  'fred' AS name
),
v2 AS
(   WITH v21 AS
    (   SELECT  alias11.name
        FROM    v1 alias11
        JOIN    v1 alias12
        ON      alias11.name = alias12.name
    )
    SELECT  name FROM v21
),
v3 AS
(   WITH v31 AS
    (   SELECT  alias21.name
        FROM    v2 alias21
        JOIN    v2 alias22
        ON      alias21.name = alias22.name
    )
    SELECT  name FROM v31
)
SELECT * FROM v3

Fails with error:

MariaDB [MYSCHEMA]> \. with-bad.sql
ERROR 1146 (42S02) at line 1 in file: 'with-bad.sql': Table 'MYSCHEMA.v1' doesn't exist

But, it does work if I have one less WITH. with-good.sql

WITH v1 AS
(   SELECT  'fred' AS name
),
v2 AS
(   WITH v21 AS
    (   SELECT  alias11.name
        FROM    v1 alias11
        JOIN    v1 alias12
        ON      alias11.name = alias12.name
    )
    SELECT  name FROM v21
)
SELECT * FROM v2

And also works if there is no join in the 3rd WITH. with-nojoin.sql

WITH v1 AS
(   SELECT  'fred' AS name
),
v2 AS
(   WITH v21 AS
    (   SELECT  alias11.name
        FROM    v1 alias11
        JOIN    v1 alias12
        ON      alias11.name = alias12.name
    )
    SELECT  name FROM v21
),
v3 AS
(   WITH v31 AS
    (   SELECT  alias21.name
        FROM    v2 alias21
    )
    SELECT  name FROM v31
)
SELECT * FROM v3

The with-bad.sql example does work in other database engines (e.g. vertica) so not a stupid typo by me (the cause of most of my errors).

Does anyone know if this is a known mariadb/mysql limit, or known bug? Feels like a bug (i.e. the extra code which causes it does not even reference v1 directly).

Any suggested "mechanical" workarounds would be very much appreciated. Actual SQL is very complex, so hoping to avoid a complete rewrite/restructure it if possible.

Thanks

Upvotes: 0

Views: 354

Answers (1)

Akina
Akina

Reputation: 42642

Do NOT use nested WITH, use chained one.

For example, your with-bad.sql should be

WITH 
v1 AS
(   SELECT  'fred' AS name
),
v21 AS
(   SELECT  alias11.name
    FROM    v1 alias11
    JOIN    v1 alias12
    ON      alias11.name = alias12.name
),
v2 AS
(   SELECT  name FROM v21
),
v31 AS
(   SELECT  alias21.name
    FROM    v2 alias21
    JOIN    v2 alias22
    ON      alias21.name = alias22.name
),
v3 AS
(   SELECT  name FROM v31
)
SELECT * FROM v3

Upvotes: 1

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