From f06ad3c972752713641ec1fee1e6cd4da2db0d64 Mon Sep 17 00:00:00 2001
From: Andrew Lamb <andrew@nerdnetworks.org>
Date: Mon, 30 Jan 2023 16:20:38 -0500
Subject: [PATCH] Add support

---
 .../expr/src/type_coercion/functions.rs       | 11 +++++--
 datafusion/optimizer/src/type_coercion.rs     | 31 ++++++++++++++++---
 2 files changed, 35 insertions(+), 7 deletions(-)

diff --git a/datafusion/expr/src/type_coercion/functions.rs b/datafusion/expr/src/type_coercion/functions.rs
index f58050eb9415d..d95596413b83d 100644
--- a/datafusion/expr/src/type_coercion/functions.rs
+++ b/datafusion/expr/src/type_coercion/functions.rs
@@ -22,8 +22,10 @@ use arrow::{
 };
 use datafusion_common::{DataFusionError, Result};
 
-/// Performs type coercion for functions Returns the data types that
-/// each argument must be coerced to match `signature`.
+/// Performs type coercion for function arguments.
+///
+/// Returns the data types to which each argument must be coerced to
+/// match `signature`.
 ///
 /// For more details on coercion in general, please see the
 /// [`type_coercion`](crate::type_coercion) module.
@@ -175,7 +177,10 @@ pub fn can_coerce_from(type_into: &DataType, type_from: &DataType) -> bool {
                 | Decimal128(_, _)
         ),
         Timestamp(TimeUnit::Nanosecond, None) => {
-            matches!(type_from, Null | Timestamp(_, None))
+            matches!(type_from, Null | Timestamp(_, None) | Utf8 | LargeUtf8)
+        }
+        Interval(_) => {
+            matches!(type_from, Utf8 | LargeUtf8)
         }
         Utf8 | LargeUtf8 => true,
         Null => can_cast_types(type_from, type_into),
diff --git a/datafusion/optimizer/src/type_coercion.rs b/datafusion/optimizer/src/type_coercion.rs
index e335c9ff5f851..5a73559532a8f 100644
--- a/datafusion/optimizer/src/type_coercion.rs
+++ b/datafusion/optimizer/src/type_coercion.rs
@@ -42,6 +42,7 @@ use datafusion_expr::{
     WindowFrame, WindowFrameBound, WindowFrameUnits,
 };
 use datafusion_expr::{ExprSchemable, Signature};
+use log::debug;
 
 use crate::utils::rewrite_preserving_name;
 use crate::{OptimizerConfig, OptimizerRule};
@@ -550,13 +551,35 @@ fn coerce_arguments_for_signature(
 
     let new_types = data_types(&current_types, signature)?;
 
-    expressions
-        .iter()
+    debug!("AAL current types: {current_types:?}");
+    debug!("AAL new types: {new_types:?}");
+
+
+    let exprs = expressions
+        .into_iter()
         .enumerate()
-        .map(|(i, expr)| expr.clone().cast_to(&new_types[i], schema))
-        .collect::<Result<Vec<_>>>()
+        .map(|(i, expr)| cast_expr(expr, &new_types[i], schema))
+        .collect::<Result<Vec<_>>>();
+
+    debug!("AAL new exprs: {new_types:?}");
+
+    exprs
 }
 
+/// Cast expr to the specified type, if possible
+fn cast_expr(expr: &Expr, to_type: &DataType, schema: &DFSchema) -> Result<Expr> {
+    // Special case until Interval coercion is handled in arrow-rs
+    match (expr, to_type) {
+        (Expr::Literal(ScalarValue::Utf8(Some(s))), DataType::Interval(_)) => {
+            parse_interval("millisecond", s.as_str()).map(Expr::Literal)
+        },
+        _ => expr.clone().cast_to(to_type, schema),
+    }
+}
+
+
+
+
 /// Returns the coerced exprs for each `input_exprs`.
 /// Get the coerced data type from `aggregate_rule::coerce_types` and add `try_cast` if the
 /// data type of `input_exprs` need to be coerced.