Nested SUBSTRING fails with INVALID_ARGUMENT error

[smola]

This works, both with positive and negative indexes:

SELECT
    repository_id,
    remote_fetch_url,
    SUBSTRING(remote_fetch_url, 18)
FROM remotes;

SELECT
    repository_id,
    remote_fetch_url,
    SUBSTRING(SUBSTRING(remote_fetch_url, 18), -4)
FROM remotes;

But this fails from gitbase-web with error:

Query Failed - unknown error: Code: INVALID_ARGUMENT syntax error at position 69 near 'substring' 

Running gitbase-0.20.0-rc1

[kuba--]

First we need to merge the fix in vitess: vitessio/vitess#4867

[smola]

Just for reference, doing a second SUBSTRING in a subquery serves as a workaround. For example:

SELECT SUBSTRING(repository_id, 1, ARRAY_LENGTH(SPLIT(repository_id, ''))-4) AS b
FROM (
SELECT SUBSTRING(remote_fetch_url, 18) AS repository_id
FROM remotes
) AS q

[kuba--]

Yep, this is clear. The problem is SQL grammar - SUBSTRING expects static string or column name, so SUBSTRING(REPLACE(...)...) should not also work.