instrumentation-knex table calculated incorrectly on nested tables

[nachogiljaldo]

What version of OpenTelemetry are you using?

@opentelemetry/instrumentation: 0.39.1

What version of Node are you using?

16.14.0

What did you do?

Used opentelemetry-knex and with nested queries, it misbehaves, potentially generating a long span name.

See nachogiljaldo@9521964 for reproduction steps.

What did you expect to see?

The code should work somewhat recursively to find the first table. And return a table (and not a subquery as was the case).

What did you see instead?

the variable table was set to be a queryBuilder, when serialized that resulted on the whole query

Additional context

The linked commit adds a potential solution, if the solution looks good I'm happy to create a PR out of it.