From e125eb40a5a326dc2e2620bcb0c2d9bb1cf582df Mon Sep 17 00:00:00 2001
From: rui-mo <rui.mo@intel.com>
Date: Mon, 16 Oct 2023 11:26:23 +0800
Subject: [PATCH] Allow decimal types in switch expr

---
 velox/expression/SwitchExpr.cpp | 33 +++++++++++++++++++++------------
 1 file changed, 21 insertions(+), 12 deletions(-)

diff --git a/velox/expression/SwitchExpr.cpp b/velox/expression/SwitchExpr.cpp
index 5f6d493ad9a4c..dc1431b531223 100644
--- a/velox/expression/SwitchExpr.cpp
+++ b/velox/expression/SwitchExpr.cpp
@@ -49,11 +49,16 @@ SwitchExpr::SwitchExpr(
 
   // Apply type checking.
   auto typeExpected = resolveType(inputTypes);
-  VELOX_CHECK(
-      *typeExpected == *this->type(),
-      "Switch expression type different than then clause. Expected {} but got Actual {}.",
-      typeExpected->toString(),
-      this->type()->toString());
+  if (typeExpected->isDecimal()) {
+    // Regard decimal types as the same regardless of precision and scale.
+    VELOX_CHECK(this->type()->isDecimal());
+  } else {
+    VELOX_CHECK(
+        *typeExpected == *this->type(),
+        "Switch expression type different than then clause. Expected {} but got Actual {}.",
+        typeExpected->toString(),
+        this->type()->toString());
+  }
 }
 
 void SwitchExpr::evalSpecialForm(
@@ -254,13 +259,17 @@ TypePtr SwitchExpr::resolveType(const std::vector<TypePtr>& argTypes) {
 
   if (hasElse) {
     auto& elseClauseType = argTypes.back();
-
-    VELOX_CHECK(
-        *elseClauseType == *expressionType,
-        "Else clause of a SWITCH statement must have the same type as 'then' clauses. "
-        "Expected {}, but got {}.",
-        expressionType->toString(),
-        elseClauseType->toString());
+    if (elseClauseType->isDecimal()) {
+      // Regard decimals as the same type regardless of precision and scale.
+      VELOX_CHECK(expressionType->isDecimal());
+    } else {
+      VELOX_CHECK(
+          *elseClauseType == *expressionType,
+          "Else clause of a SWITCH statement must have the same type as 'then' clauses. "
+          "Expected {}, but got {}.",
+          expressionType->toString(),
+          elseClauseType->toString());
+    }
   }
 
   return expressionType;