Better error for null parameter

Author: theirix

datafusion/functions-aggregate/src/utils.rs

@@ -54,6 +54,11 @@ pub(crate) fn validate_percentile_expr(
     let percentile = match scalar_value {
         ScalarValue::Float32(Some(value)) => value as f64,
         ScalarValue::Float64(Some(value)) => value,
+        ScalarValue::Float32(None) | ScalarValue::Float64(None) => {
+            return plan_err!(
+                "Percentile value for '{fn_name}' must be Float32 or Float64 literal (got null)"
+            );
+        }
         sv => {
             return plan_err!(
                 "Percentile value for '{fn_name}' must be Float32 or Float64 literal (got data type {})",

datafusion/sqllogictest/test_files/aggregate.slt

@@ -1991,6 +1991,9 @@ SELECT APPROX_PERCENTILE_CONT(0.5) WITHIN GROUP (ORDER BY v) FROM (VALUES (CAST(
 ----
 NULL
 
+query error DataFusion error: Error during planning: Percentile value for 'APPROX_PERCENTILE_CONT' must be Float32 or Float64 literal \(got null\)
+SELECT APPROX_PERCENTILE_CONT(NULL) WITHIN GROUP (ORDER BY v) FROM (VALUES (CAST(NULL as INT))) as t (v);
+
 # percentile_cont_with_weight_with_nulls
 query R
 SELECT APPROX_PERCENTILE_CONT_WITH_WEIGHT(w, 0.5) WITHIN GROUP (ORDER BY v)