I'm trying to run some MySQL-compatible SQL that uses SIGN(...) , but TiDB doesn't recognize that function…

I'm trying to run some MySQL-compatible SQL that uses SIGN(...) , but TiDB doesn't recognize that function…: a task in MiMo-V2.6-RL-harbor-code: MiMo-V2.6-RL Code (Harbor) (Harbor dataset). The implementation should behave consistently with TiDB’s existing built-in SQL functions. The exact…

The task

The implementation should behave consistently with TiDB’s existing built-in SQL functions. The exact internal structure, helper functions, registration location, and validation path are left to the implementer.

Part of FineEnvs/MiMo-V2.6-RL-harbor-code.