Support labels in query

[Omega359]

As seen in Datafusion when attempting to parse the sqlite test suite:

External error: task 27341 panicked with message "called Result::unwrap() on an Err value: ParseError { kind: UnexpectedToken("label-1"), loc: Location { file: "../../datafusion-testing/data/sqlite/random/select/slt_good_21.slt", line: 47, upper: None } }"

The line referenced above is:

query I rowsort label-1 
SELECT + 94 / - col2 + col1 + 9 FROM tab0 AS cor0 
---- 
12 
93 
99

I believe the issue is the new retry code does not account for labels as documented @ https://sqlite.org/sqllogictest/doc/trunk/about.wiki

[skyzh]

likely introduced by #239?

[skyzh]

@mikel879881 has been blocked from the repo

[xxchan]

Yes, label was removed from parser in #239, because it's actually never supported in runner. It seems it's used in sqlite's test suite. You may use 0.24.0 for now. PR to add it back is welcome!

[fuyufjh]

Sorry about that, I'll try to see if I can bring back this feature. Unfortunately, there isn't a test case that covers this functionality (label).

[fuyufjh]

Oh, wait, I must clarify one thing. As mentioned in #238,

Also removed label from QueryExpect::Results because it's never used.

The <label> was supported by Parser, but never functions as expected:

The argument is also optional. If included, sqllogictest stores a hash of the results of this query under the given label. If the label is reused, then sqllogictest verifies that the results are the same. This can be used to verify that two or more queries in the same test script that are logically equivalent always generate the same output.

Thus, <label> is actually a missing feature compared with sqllogictest. Feel free to contribute.

[Omega359]

If I find time this month I may work on this as it would be a nice feature to have.