Method register_udf

datafusion/core/src/execution/context/mod.rs:1615–1618

Registers a scalar UDF within this context. Note in SQL queries, function names are looked up using lowercase unless the query uses quotes. For example, - `SELECT MY_FUNC(x)...` will look for a function named `"my_func"` - `SELECT "my_FUNC"(x)` will look for a function named `"my_FUNC"` Any functions registered with the udf name or its aliases will be overwritten with this new function

(&self, f: ScalarUDF)

    ///
    /// Any functions registered with the udf name or its aliases will be overwritten with this new function
    pub fn register_udf(&self, f: ScalarUDF) {
        let mut state = self.state.write();
        state.register_udf(Arc::new(f)).ok();
    }

    /// Registers a higher-order function within this context.
    ///