sql: remove TODO about #13642 & revert unintentional math function changes

[hueypark]

The title says it all.

[blathers-crl]

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[cockroach-teamcity]

This change is 

[blathers-crl]

❌ The GitHub CI (Cockroach) build has failed on 12424f0b.

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[blathers-crl]

Thank you for updating your pull request.

Before a member of our team reviews your PR, I have a few suggestions for tidying it up for review:

• We generally try and keep pull requests to one commit. Please squash your commits, and re-push with --force.
• Please ensure your pull request description contains a release note - this can be the same as the one in your commit message.
• When CI has completed, please ensure no errors have appeared.

I was unable to automatically find a reviewer. You can try CCing one of the following members:

• A person you worked with closely on this PR.
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• Join our community slack channel and ask on #contributors.
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[yuzefovich]

Thanks for the fix!

A couple of nits: we usually don't have periods in the PR titles, and the PR description is missing

Reviewed 1 of 1 files at r1, 2 of 2 files at r2.
Reviewable status: complete! 1 of 0 LGTMs obtained

[hueypark]

Thank you for the review!

Reviewable status: complete! 1 of 0 LGTMs obtained

[yuzefovich]

bors r=yuzefovich

[craig]

Build failed

• GitHub CI (Cockroach)

[yuzefovich]

CI flake.

bors r=yuzefovich

[craig]

Build succeeded

• GitHub CI (Cockroach)