update billing usage month args case-insensitive

Author: smallfish

src/query/task_support/src/table_functions/billing_usage_daily.rs

@@ -224,14 +224,24 @@ impl BillingUsageDailyArgsParsed {
             ));
         }
 
-        let month = args
-            .get("month")
-            .and_then(|v| v.as_string().cloned())
-            .ok_or_else(|| {
-                ErrorCode::BadArguments(
-                    "billing_usage_daily requires named string argument: month".to_string(),
-                )
-            })?;
+        let mut month = None;
+        for (k, v) in &args {
+            match k.to_lowercase().as_str() {
+                "month" => month = v.as_string().cloned(),
+                _ => {
+                    return Err(ErrorCode::BadArguments(format!(
+                        "unknown param {} for billing_usage_daily",
+                        k
+                    )));
+                }
+            }
+        }
+
+        let month = month.ok_or_else(|| {
+            ErrorCode::BadArguments(
+                "billing_usage_daily requires named string argument: month".to_string(),
+            )
+        })?;
 
         validate_month(&month)?;
         Ok(Self { month })
@@ -360,6 +370,17 @@ mod tests {
         assert_eq!(parsed.month, "2026-03");
     }
 
+    #[test]
+    fn test_parse_args_accepts_uppercase_named_month() {
+        let args = TableArgs::new_named(HashMap::from([(
+            "MONTH".to_string(),
+            Scalar::String("2026-03".to_string()),
+        )]));
+
+        let parsed = BillingUsageDailyArgsParsed::parse(&args).unwrap();
+        assert_eq!(parsed.month, "2026-03");
+    }
+
     #[test]
     fn test_parse_args_rejects_non_named_or_invalid_month() {
         let positioned = TableArgs::new_positioned(vec![Scalar::String("2026-03".to_string())]);