{inq: []} produces invalid SQL

[bitmage]

This query:

Project.find({
  fields: { id: true },
  where: { id: { inq: [] } } }
}, function(){})

Produces this SQL:

SELECT [id] FROM [dbo].[Project]
WHERE 0
ORDER BY [id]

Which is invalid, and fails with this error:

RequestError: An expression of non-boolean type specified in a context where a condition is expected, near 'ORDER'.

The query presented is generated by the changes method, which is part of the Loopback replication implementation. This particular query will be generated when there are no changes detected.

I think the changes method should ignore this case and not send a query. I will send a separate issue/pull request for that.

I bring up the issue here though, because I think that the MSSQL driver should probably also gracefully handle this situation by creating a no-op query. Something like this:

SELECT [id] FROM [dbo].[Project]
WHERE 0 = 1
ORDER BY [id]

or...

WHERE [id] IS NULL

or...

WHERE [id] IN (NULL)

I'm concerned about the latter two though, as they might incorrectly produce results in the case of a NULLABLE field. Is there a better way to form such a query? I'm happy to make a pull request if I can get some feedback on what the correct solution would be.

Thanks!

[raymondfeng]

Good catch. WHERE 0 is valid in MySql. For Mssql, it can be 0 = 1. Please submit a patch.

[raymondfeng]

Fixed