From bdbce77227d16a1fe731dc4aa55b108f291fd24d Mon Sep 17 00:00:00 2001
From: Kikyou1997 <33112463+Kikyou1997@users.noreply.github.com>
Date: Wed, 7 Sep 2022 20:32:47 +0800
Subject: [PATCH] [fix](nereids) cast left child of TimestampArithmetic to
 wrong type in BindFunction (#12423)

---
 .../org/apache/doris/nereids/rules/analysis/BindFunction.java   | 2 +-
 .../doris/nereids/trees/expressions/TimestampArithmetic.java    | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/rules/analysis/BindFunction.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/rules/analysis/BindFunction.java
index 567d2169ff..d1a4a4cd2c 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/rules/analysis/BindFunction.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/rules/analysis/BindFunction.java
@@ -175,7 +175,7 @@ public class BindFunction implements AnalysisRuleFactory {
                 } catch (Exception e) {
                     // ignore
                 }
-                if (!left.getDataType().isDateType() && arithmetic.getTimeUnit().isDateTimeUnit()) {
+                if (!left.getDataType().isDateType() && !arithmetic.getTimeUnit().isDateTimeUnit()) {
                     left = arithmetic.left().castTo(DateType.INSTANCE);
                 }
             }
diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/TimestampArithmetic.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/TimestampArithmetic.java
index ec5c5ce02f..c288698451 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/TimestampArithmetic.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/TimestampArithmetic.java
@@ -36,6 +36,7 @@ import java.util.List;
  * Describes the addition and subtraction of time units from timestamps.
  * Arithmetic expressions on timestamps are syntactic sugar.
  * They are executed as function call exprs in the BE.
+ * Example: '1996-01-01' + INTERVAL '3' month;
  * TODO: we need to rethink this, and maybe need to add a new type of Interval then implement IntervalLiteral as others
  */
 public class TimestampArithmetic extends Expression implements BinaryExpression {