From f7ae38ad6bf59136f01fc46141cf657a203c9053 Mon Sep 17 00:00:00 2001
From: even986025158 <39552698+even986025158@users.noreply.github.com>
Date: Fri, 11 Oct 2024 19:00:57 +0800
Subject: [PATCH] [Enhancement]implement dayofweek in FE (#51453)

Signed-off-by: evenhuang <986025158@qq.com>
(cherry picked from commit fb410393146ed808d5c15d6ba0ce99f940fb7ec8)

Signed-off-by: even986025158 <39552698+even986025158@users.noreply.github.com>
---
 .../rewrite/ScalarOperatorFunctions.java      | 28 ++++++++++++++++++-
 .../rewrite/ScalarOperatorFunctionsTest.java  | 15 ++++++++++
 2 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/fe/fe-core/src/main/java/com/starrocks/sql/optimizer/rewrite/ScalarOperatorFunctions.java b/fe/fe-core/src/main/java/com/starrocks/sql/optimizer/rewrite/ScalarOperatorFunctions.java
index 82accbf03334e..f336b276a2ecb 100644
--- a/fe/fe-core/src/main/java/com/starrocks/sql/optimizer/rewrite/ScalarOperatorFunctions.java
+++ b/fe/fe-core/src/main/java/com/starrocks/sql/optimizer/rewrite/ScalarOperatorFunctions.java
@@ -182,7 +182,33 @@ public static ConstantOperator dateDiff(ConstantOperator first, ConstantOperator
                 first.getDatetime().truncatedTo(ChronoUnit.DAYS)).toDays());
     }
 
-    @ConstantFunction(name = "years_add", argTypes = {DATETIME, INT}, returnType = DATETIME, isMonotonic = true)
+    @ConstantFunction.List(list = {
+            @ConstantFunction(name = "to_days", argTypes = {DATETIME}, returnType = INT, isMonotonic = true),
+            @ConstantFunction(name = "to_days", argTypes = {DATE}, returnType = INT, isMonotonic = true)
+    })
+    public static ConstantOperator to_days(ConstantOperator first) {
+        ConstantOperator second = ConstantOperator.createDatetime(LocalDateTime.of(0000, 01, 01, 00, 00, 00));
+        return ConstantOperator.createInt((int) Duration.between(
+                second.getDatetime().truncatedTo(ChronoUnit.DAYS),
+                first.getDatetime().truncatedTo(ChronoUnit.DAYS)).toDays());
+    }
+
+    @ConstantFunction.List(list = {
+            @ConstantFunction(name = "dayofweek", argTypes = {DATETIME}, returnType = INT),
+            @ConstantFunction(name = "dayofweek", argTypes = {DATE}, returnType = INT),
+            @ConstantFunction(name = "dayofweek", argTypes = {INT}, returnType = INT)
+    })
+    public static ConstantOperator dayofweek(ConstantOperator date) {
+        // LocalDateTime.getDayOfWeek is return day of the week, such as monday is 1 and sunday is 7.
+        // function of dayofweek in starrocks monday is 2 and sunday is 1, so need mod 7 and plus 1.
+        return ConstantOperator.createInt((date.getDatetime().getDayOfWeek().getValue()) % 7 + 1);
+    }
+
+    @ConstantFunction.List(list = {
+            @ConstantFunction(name = "years_add", argTypes = {DATETIME,
+                    INT}, returnType = DATETIME, isMonotonic = true),
+            @ConstantFunction(name = "years_add", argTypes = {DATE, INT}, returnType = DATE, isMonotonic = true)
+    })
     public static ConstantOperator yearsAdd(ConstantOperator date, ConstantOperator year) {
         return ConstantOperator.createDatetime(date.getDatetime().plusYears(year.getInt()));
     }
diff --git a/fe/fe-core/src/test/java/com/starrocks/sql/optimizer/rewrite/ScalarOperatorFunctionsTest.java b/fe/fe-core/src/test/java/com/starrocks/sql/optimizer/rewrite/ScalarOperatorFunctionsTest.java
index 68fd04cc90351..223c8052475e0 100644
--- a/fe/fe-core/src/test/java/com/starrocks/sql/optimizer/rewrite/ScalarOperatorFunctionsTest.java
+++ b/fe/fe-core/src/test/java/com/starrocks/sql/optimizer/rewrite/ScalarOperatorFunctionsTest.java
@@ -118,6 +118,21 @@ public void dateDiff() {
         assertEquals(-1572, ScalarOperatorFunctions.dateDiff(O_DT_20101202_023010, O_DT_20150323_092355).getInt());
     }
 
+    @Test
+    public void dayofweek() {
+        ConstantOperator testDate = ConstantOperator.createDatetime(LocalDateTime.of(2024, 2, 3, 13, 4, 5));
+        assertEquals(7,
+                ScalarOperatorFunctions.dayofweek(testDate).getInt());
+
+        testDate = ConstantOperator.createDatetime(LocalDateTime.of(2024, 2, 4, 13, 4, 5));
+        assertEquals(1,
+                ScalarOperatorFunctions.dayofweek(testDate).getInt());
+
+        testDate = ConstantOperator.createDatetime(LocalDateTime.of(2024, 2, 5, 13, 4, 5));
+        assertEquals(2,
+                ScalarOperatorFunctions.dayofweek(testDate).getInt());
+    }
+
     @Test
     public void yearsAdd() {
         assertEquals("2025-03-23T09:23:55",