From c96889c1320d84182575588f3642af891bd173ed Mon Sep 17 00:00:00 2001
From: zhaochun <zhaochun@baidu.com>
Date: Mon, 23 Sep 2019 17:06:46 +0800
Subject: [PATCH] Support cast datetime to decimal

---
 be/src/exprs/decimal_operators.cpp                 | 14 ++++++++++++++
 be/src/exprs/decimal_operators.h                   |  1 +
 be/src/exprs/decimalv2_operators.cpp               | 13 +++++++++++++
 be/src/exprs/decimalv2_operators.h                 |  1 +
 .../java/org/apache/doris/analysis/CastExpr.java   |  4 ++--
 5 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/be/src/exprs/decimal_operators.cpp b/be/src/exprs/decimal_operators.cpp
index 88b6e0829bb30a..8c19b39735c432 100644
--- a/be/src/exprs/decimal_operators.cpp
+++ b/be/src/exprs/decimal_operators.cpp
@@ -76,6 +76,20 @@ DecimalVal DecimalOperators::cast_to_decimal_val(
     return result;
 }
 
+DecimalVal DecimalOperators::cast_to_decimal_val(
+        FunctionContext* context, const DateTimeVal& val) {
+    if (val.is_null) {
+        return DecimalVal::null();
+    }
+
+    DateTimeValue dt_value = DateTimeValue::from_datetime_val(val);
+    
+    DecimalValue dv = dt_value.to_int64();
+    DecimalVal result;
+    dv.to_decimal_val(&result);
+    return result;
+}
+
 DecimalVal DecimalOperators::cast_to_decimal_val(
         FunctionContext* context, const StringVal& val) {
     if (val.is_null) {
diff --git a/be/src/exprs/decimal_operators.h b/be/src/exprs/decimal_operators.h
index 766c734f712222..a46532ca5d3d6e 100644
--- a/be/src/exprs/decimal_operators.h
+++ b/be/src/exprs/decimal_operators.h
@@ -41,6 +41,7 @@ class DecimalOperators {
     static DecimalVal cast_to_decimal_val(FunctionContext*, const LargeIntVal&);
     static DecimalVal cast_to_decimal_val(FunctionContext*, const FloatVal&);
     static DecimalVal cast_to_decimal_val(FunctionContext*, const DoubleVal&);
+    static DecimalVal cast_to_decimal_val(FunctionContext*, const DateTimeVal&);
     static DecimalVal cast_to_decimal_val(FunctionContext*, const StringVal&);
 
     static BooleanVal cast_to_boolean_val(FunctionContext*, const DecimalVal&);
diff --git a/be/src/exprs/decimalv2_operators.cpp b/be/src/exprs/decimalv2_operators.cpp
index b15bc40863b1f8..0a5732123b5da2 100644
--- a/be/src/exprs/decimalv2_operators.cpp
+++ b/be/src/exprs/decimalv2_operators.cpp
@@ -76,6 +76,19 @@ DecimalV2Val DecimalV2Operators::cast_to_decimalv2_val(
     return result;
 }
 
+DecimalV2Val DecimalV2Operators::cast_to_decimalv2_val(
+        FunctionContext* context, const DateTimeVal& val) {
+    if (val.is_null) {
+        return DecimalV2Val::null();
+    }
+
+    DateTimeValue dt_value = DateTimeValue::from_datetime_val(val);
+    DecimalV2Value dv(dt_value.to_int64(), 0);
+    DecimalV2Val result;
+    dv.to_decimal_val(&result);
+    return result;
+}
+
 DecimalV2Val DecimalV2Operators::cast_to_decimalv2_val(
         FunctionContext* context, const StringVal& val) {
     if (val.is_null) {
diff --git a/be/src/exprs/decimalv2_operators.h b/be/src/exprs/decimalv2_operators.h
index 5a404b98992b27..8030985d46566c 100644
--- a/be/src/exprs/decimalv2_operators.h
+++ b/be/src/exprs/decimalv2_operators.h
@@ -41,6 +41,7 @@ class DecimalV2Operators {
     static DecimalV2Val cast_to_decimalv2_val(FunctionContext*, const LargeIntVal&);
     static DecimalV2Val cast_to_decimalv2_val(FunctionContext*, const FloatVal&);
     static DecimalV2Val cast_to_decimalv2_val(FunctionContext*, const DoubleVal&);
+    static DecimalV2Val cast_to_decimalv2_val(FunctionContext*, const DateTimeVal&);
     static DecimalV2Val cast_to_decimalv2_val(FunctionContext*, const StringVal&);
 
     static BooleanVal cast_to_boolean_val(FunctionContext*, const DecimalV2Val&);
diff --git a/fe/src/main/java/org/apache/doris/analysis/CastExpr.java b/fe/src/main/java/org/apache/doris/analysis/CastExpr.java
index 18334f1b44e9ff..ba1c81977e19bf 100644
--- a/fe/src/main/java/org/apache/doris/analysis/CastExpr.java
+++ b/fe/src/main/java/org/apache/doris/analysis/CastExpr.java
@@ -103,8 +103,8 @@ public static void initBuiltins(FunctionSet functionSet) {
                 if (fromType.isStringType() && toType.isBoolean()) {
                     continue;
                 }
-                // Disable casting from boolean/timestamp to decimal
-                if ((fromType.isBoolean() || fromType.isDateType()) && 
+                // Disable casting from boolean to decimal
+                if (fromType.isBoolean() &&
                         (toType == Type.DECIMAL || toType == Type.DECIMALV2)) {
                     continue;
                 }