Add new function toLastDayOfMonth

docs/en/sql-reference/functions/date-time-functions.md

@@ -393,6 +393,13 @@ This is a generalization of other functions named `toStartOf*`. For example,
 `toStartOfInterval(t, INTERVAL 1 day)` returns the same as `toStartOfDay(t)`,
 `toStartOfInterval(t, INTERVAL 15 minute)` returns the same as `toStartOfFifteenMinutes(t)` etc.
 
+## toLastDayOfMonth {#toLastDayOfMonth}
+
+Rounds up a date or date with time to the last day of the month.
+Returns the date.
+
+Alias: `LAST_DAY`.
+
 ## toTime {#totime}
 
 Converts a date with time to a certain fixed date, while preserving the time.

src/Common/DateLUTImpl.h

@@ -360,6 +360,27 @@ public:
             return toDayNum(LUTIndex(i - (lut[i].day_of_month - 1)));
     }
 
+    /// Round up to last day of month.
+    template <typename DateOrTime>
+    inline Time toLastDayOfMonth(DateOrTime v) const
+    {
+        const LUTIndex i = toLUTIndex(v);
+        if constexpr (std::is_unsigned_v<DateOrTime> || std::is_same_v<DateOrTime, DayNum>)
+            return lut_saturated[i - lut[i].day_of_month + lut[i].days_in_month].date;
+        else
+            return lut[i - lut[i].day_of_month + lut[i].days_in_month].date;
+    }
+
+    template <typename DateOrTime>
+    inline auto toLastDayNumOfMonth(DateOrTime v) const
+    {
+        const LUTIndex i = toLUTIndex(v);
+        if constexpr (std::is_unsigned_v<DateOrTime> || std::is_same_v<DateOrTime, DayNum>)
+            return toDayNum(LUTIndexWithSaturation(i - lut[i].day_of_month + lut[i].days_in_month));
+        else
+            return toDayNum(LUTIndex(i - lut[i].day_of_month + lut[i].days_in_month));
+    }
+
     /// Round down to start of quarter.
     template <typename DateOrTime>
     inline auto toFirstDayNumOfQuarter(DateOrTime v) const

src/Common/tests/gtest_DateLUTImpl.cpp

@@ -142,6 +142,8 @@ TEST(DateLUTTest, TimeValuesInMiddleOfRange)
     EXPECT_EQ(lut.addYears(time, 10), 1884270011 /*time_t*/);
     EXPECT_EQ(lut.timeToString(time), "2019-09-16 19:20:11" /*std::string*/);
     EXPECT_EQ(lut.dateToString(time), "2019-09-16" /*std::string*/);
+    EXPECT_EQ(lut.toLastDayOfMonth(time), 1569790800 /*time_t*/);
+    EXPECT_EQ(lut.toLastDayNumOfMonth(time), DayNum(18169) /*DayNum*/);
 }
 
 
@@ -202,6 +204,8 @@ TEST(DateLUTTest, TimeValuesAtLeftBoderOfRange)
     EXPECT_EQ(lut.addYears(time, 10), 315532800 /*time_t*/);
     EXPECT_EQ(lut.timeToString(time), "1970-01-01 00:00:00" /*std::string*/);
     EXPECT_EQ(lut.dateToString(time), "1970-01-01" /*std::string*/);
+    EXPECT_EQ(lut.toLastDayOfMonth(time), 2592000 /*time_t*/);
+    EXPECT_EQ(lut.toLastDayNumOfMonth(time), DayNum(30) /*DayNum*/);
 }
 
 TEST(DateLUTTest, TimeValuesAtRightBoderOfRangeOfOldLUT)
@@ -264,6 +268,8 @@ TEST(DateLUTTest, TimeValuesAtRightBoderOfRangeOfOldLUT)
 
     EXPECT_EQ(lut.timeToString(time), "2106-01-31 01:17:53" /*std::string*/);
     EXPECT_EQ(lut.dateToString(time), "2106-01-31" /*std::string*/);
+    EXPECT_EQ(lut.toLastDayOfMonth(time), 4294339200 /*time_t*/); // 2016-01-01
+    EXPECT_EQ(lut.toLastDayNumOfMonth(time), DayNum(49703));
 }
 
 

src/Functions/DateTimeTransforms.h

@@ -174,6 +174,30 @@ struct ToStartOfMonthImpl
     using FactorTransform = ZeroTransform;
 };
 
+struct ToLastDayOfMonthImpl
+{
+    static constexpr auto name = "toLastDayOfMonth";
+
+    static inline UInt16 execute(Int64 t, const DateLUTImpl & time_zone)
+    {
+        return time_zone.toLastDayNumOfMonth(time_zone.toDayNum(t));
+    }
+    static inline UInt16 execute(UInt32 t, const DateLUTImpl & time_zone)
+    {
+        return time_zone.toLastDayNumOfMonth(time_zone.toDayNum(t));
+    }
+    static inline UInt16 execute(Int32 d, const DateLUTImpl & time_zone)
+    {
+        return time_zone.toLastDayNumOfMonth(ExtendedDayNum(d));
+    }
+    static inline UInt16 execute(UInt16 d, const DateLUTImpl & time_zone)
+    {
+        return time_zone.toLastDayNumOfMonth(DayNum(d));
+    }
+
+    using FactorTransform = ZeroTransform;
+};
+
 struct ToStartOfQuarterImpl
 {
     static constexpr auto name = "toStartOfQuarter";

src/Functions/registerFunctionsDateTime.cpp

@@ -20,6 +20,7 @@ void registerFunctionToISOYear(FunctionFactory &);
 void registerFunctionToCustomWeek(FunctionFactory &);
 void registerFunctionToModifiedJulianDay(FunctionFactory &);
 void registerFunctionToStartOfMonth(FunctionFactory &);
+void registerFunctionToLastDayOfMonth(FunctionFactory &);
 void registerFunctionToStartOfQuarter(FunctionFactory &);
 void registerFunctionToStartOfYear(FunctionFactory &);
 void registerFunctionToStartOfMinute(FunctionFactory &);
@@ -91,6 +92,7 @@ void registerFunctionsDateTime(FunctionFactory & factory)
     registerFunctionToCustomWeek(factory);
     registerFunctionToModifiedJulianDay(factory);
     registerFunctionToStartOfMonth(factory);
+    registerFunctionToLastDayOfMonth(factory);
     registerFunctionToStartOfQuarter(factory);
     registerFunctionToStartOfYear(factory);
     registerFunctionToStartOfSecond(factory);

src/Functions/toLastDayOfMonth.cpp

@@ -0,0 +1,21 @@
+#include <Functions/FunctionFactory.h>
+#include <Functions/DateTimeTransforms.h>
+#include <Functions/FunctionDateOrDateTimeToSomething.h>
+
+
+namespace DB
+{
+
+using FunctionToLastDayOfMonth = FunctionDateOrDateTimeToSomething<DataTypeDate, ToLastDayOfMonthImpl>;
+
+void registerFunctionToLastDayOfMonth(FunctionFactory & factory)
+{
+    factory.registerFunction<FunctionToLastDayOfMonth>();
+
+    /// MysQL compatibility alias.
+    factory.registerFunction<FunctionToLastDayOfMonth>("LAST_DAY", FunctionFactory::CaseInsensitive);
+}
+
+}
+
+

utils/db-generator/query_db_generator.cpp

@@ -229,7 +229,7 @@ std::map<std::string, FuncRet> func_to_return_type = {
         {"torelativeweeknum", FuncRet(Type::i, "")}, {"torelativedaynum", FuncRet(Type::i, "")}, {"torelativehournum", FuncRet(Type::i, "")},
         {"torelativeminutenum", FuncRet(Type::i, "")}, {"torelativesecondsnum", FuncRet(Type::i, "")}, {"datediff", FuncRet(Type::d | Type::dt, "")},
         {"formatdatetime", FuncRet(Type::s, "")}, {"now", FuncRet(Type::dt | Type::d, "now()")}, {"today", FuncRet(Type::d | Type::dt, "today()")},
-        {"yesterday", FuncRet(Type::d | Type::dt, "yesterday()")}
+        {"yesterday", FuncRet(Type::d | Type::dt, "yesterday()")}, {"tolastdayofmonth", FuncRet(Type::dt | Type::d, "")}
 };
 
 std::set<std::string> func_args_same_types = {
@@ -253,7 +253,7 @@ std::map<std::string, ColumnType> func_to_param_type = {
         {"tostartofinterval", Type::d | Type::dt}, {"totime", Type::d | Type::dt}, {"torelativehonthnum", Type::d | Type::dt},
         {"torelativeweeknum", Type::d | Type::dt}, {"torelativedaynum", Type::d | Type::dt}, {"torelativehournum", Type::d | Type::dt},
         {"torelativeminutenum", Type::d | Type::dt}, {"torelativesecondnum", Type::d | Type::dt}, {"datediff", Type::d | Type::dt},
-        {"formatdatetime", Type::dt}
+        {"formatdatetime", Type::dt}, {"tolastdayofmonth", Type::d | Type::dt}
 };