Add Day_Of_Week Function As An Alias Of DayOfWeek

core/src/main/java/org/opensearch/sql/expression/DSL.java

@@ -338,6 +338,10 @@ public static FunctionExpression day_of_year(Expression... expressions) {
     return compile(FunctionProperties.None, BuiltinFunctionName.DAY_OF_YEAR, expressions);
   }
 
+  public static FunctionExpression day_of_week(Expression... expressions) {
+    return compile(FunctionProperties.None, BuiltinFunctionName.DAY_OF_WEEK, expressions);
+  }
+
   public static FunctionExpression from_days(Expression... expressions) {
     return compile(FunctionProperties.None, BuiltinFunctionName.FROM_DAYS, expressions);
   }

core/src/main/java/org/opensearch/sql/expression/datetime/DateTimeFunction.java

@@ -101,7 +101,8 @@ public void register(BuiltinFunctionRepository repository) {
     repository.register(day());
     repository.register(dayName());
     repository.register(dayOfMonth());
-    repository.register(dayOfWeek());
+    repository.register(dayOfWeek(BuiltinFunctionName.DAYOFWEEK.getName()));
+    repository.register(dayOfWeek(BuiltinFunctionName.DAY_OF_WEEK.getName()));
     repository.register(dayOfYear(BuiltinFunctionName.DAYOFYEAR));
     repository.register(dayOfYear(BuiltinFunctionName.DAY_OF_YEAR));
     repository.register(from_days());
@@ -349,8 +350,8 @@ private DefaultFunctionResolver dayOfMonth() {
    * DAYOFWEEK(STRING/DATE/DATETIME/TIMESTAMP).
    * return the weekday index for date (1 = Sunday, 2 = Monday, …, 7 = Saturday).
    */
-  private DefaultFunctionResolver dayOfWeek() {
-    return define(BuiltinFunctionName.DAYOFWEEK.getName(),
+  private DefaultFunctionResolver dayOfWeek(FunctionName name) {
+    return define(name,
         impl(nullMissingHandling(DateTimeFunction::exprDayOfWeek), INTEGER, DATE),
         impl(nullMissingHandling(DateTimeFunction::exprDayOfWeek), INTEGER, DATETIME),
         impl(nullMissingHandling(DateTimeFunction::exprDayOfWeek), INTEGER, TIMESTAMP),

core/src/main/java/org/opensearch/sql/expression/function/BuiltinFunctionName.java

@@ -69,6 +69,7 @@ public enum BuiltinFunctionName {
   DAYOFMONTH(FunctionName.of("dayofmonth")),
   DAYOFWEEK(FunctionName.of("dayofweek")),
   DAYOFYEAR(FunctionName.of("dayofyear")),
+  DAY_OF_WEEK(FunctionName.of("day_of_week")),
   DAY_OF_YEAR(FunctionName.of("day_of_year")),
   FROM_DAYS(FunctionName.of("from_days")),
   FROM_UNIXTIME(FunctionName.of("from_unixtime")),

core/src/test/java/org/opensearch/sql/expression/datetime/DateTimeFunctionTest.java

@@ -458,6 +458,78 @@ public void dayOfWeek() {
     assertEquals(integerValue(1), eval(expression));
   }
 
+  public void testDayOfWeekWithUnderscoress(FunctionExpression dateExpression, int dayOfWeek) {
+    assertEquals(INTEGER, dateExpression.type());
+    assertEquals(integerValue(dayOfWeek), eval(dateExpression));
+  }
+
+  @Test
+  public void dayOfWeekWithUnderscores() {
+    lenient().when(nullRef.valueOf(env)).thenReturn(nullValue());
+    lenient().when(missingRef.valueOf(env)).thenReturn(missingValue());
+
+    FunctionExpression expression1 = DSL.day_of_week(DSL.literal(new ExprDateValue("2020-08-07")));
+    FunctionExpression expression2 = DSL.day_of_week(DSL.literal(new ExprDateValue("2020-08-09")));
+    FunctionExpression expression3 = DSL.day_of_week(DSL.literal("2020-08-09"));
+    FunctionExpression expression4 = DSL.day_of_week(DSL.literal("2020-08-09 01:02:03"));
+
+    assertAll(
+        () -> testDayOfWeekWithUnderscoress(expression1, 6),
+        () -> assertEquals("day_of_week(DATE '2020-08-07')", expression1.toString()),
+
+        () -> testDayOfWeekWithUnderscoress(expression2, 1),
+        () -> assertEquals("day_of_week(DATE '2020-08-09')", expression2.toString()),
+
+
+        () -> testDayOfWeekWithUnderscoress(expression3, 1),
+        () -> assertEquals("day_of_week(\"2020-08-09\")", expression3.toString()),
+
+        () -> testDayOfWeekWithUnderscoress(expression4, 1),
+        () -> assertEquals("day_of_week(\"2020-08-09 01:02:03\")", expression4.toString())
+    );
+  }
+
+  public void testInvalidDayOfWeek(String date) {
+    FunctionExpression expression = DSL.day_of_year(DSL.literal(new ExprDateValue(date)));
+    eval(expression);
+  }
+
+  @Test
+  public void dayOfWeekWithUnderscoresLeapYear() {
+    lenient().when(nullRef.valueOf(env)).thenReturn(nullValue());
+    lenient().when(missingRef.valueOf(env)).thenReturn(missingValue());
+
+    //Feb. 29 of a leap year
+    testDayOfWeekWithUnderscoress(DSL.day_of_week(DSL.literal("2020-02-29")), 7);
+
+    //day after Feb. 29 of a leap year
+    testDayOfWeekWithUnderscoress(DSL.day_of_week(DSL.literal("2020-03-01")), 1);
+
+    //Feb. 28 of a non-leap year
+    testDayOfWeekWithUnderscoress(DSL.day_of_week(DSL.literal("2021-02-28")), 1);
+
+    //Feb. 29 of a non-leap year
+    assertThrows(SemanticCheckException.class, () ->  testInvalidDayOfWeek("2021-02-29"));
+
+  }
+
+  @Test
+  public void dayOfWeekWithUnderscoresInvalidArgument() {
+    when(nullRef.type()).thenReturn(DATE);
+    when(missingRef.type()).thenReturn(DATE);
+    assertEquals(nullValue(), eval(DSL.day_of_week(nullRef)));
+    assertEquals(missingValue(), eval(DSL.day_of_week(missingRef)));
+
+    //40th day of the month
+    assertThrows(SemanticCheckException.class, () ->  testInvalidDayOfWeek("2021-02-40"));
+
+    //13th month of the year
+    assertThrows(SemanticCheckException.class, () ->  testInvalidDayOfWeek("2021-13-29"));
+
+    //incorrect format
+    assertThrows(SemanticCheckException.class, () ->  testInvalidDayOfWeek("asdfasdf"));
+  }
+
   @Test
   public void dayOfYear() {
     when(nullRef.type()).thenReturn(DATE);

docs/user/dql/functions.rst

@@ -1434,6 +1434,8 @@ Description
 
 Usage: dayofweek(date) returns the weekday index for date (1 = Sunday, 2 = Monday, …, 7 = Saturday).
 
+The `day_of_week` function is also provided as an alias.
+
 Argument type: STRING/DATE/DATETIME/TIMESTAMP
 
 Return type: INTEGER
@@ -1448,6 +1450,47 @@ Example::
     | 4                               |
     +---------------------------------+
 
+    os> SELECT DAYOFWEEK(DATETIME('2020-08-26 00:00:00'))
+    fetched rows / total rows = 1/1
+    +----------------------------------------------+
+    | DAYOFWEEK(DATETIME('2020-08-26 00:00:00'))   |
+    |----------------------------------------------|
+    | 4                                            |
+    +----------------------------------------------+
+
+    os> SELECT DAYOFWEEK(TIMESTAMP('2020-08-26 00:00:00'))
+    fetched rows / total rows = 1/1
+    +-----------------------------------------------+
+    | DAYOFWEEK(TIMESTAMP('2020-08-26 00:00:00'))   |
+    |-----------------------------------------------|
+    | 4                                             |
+    +-----------------------------------------------+
+
+    os> SELECT DAY_OF_WEEK(DATE('2020-08-26'))
+    fetched rows / total rows = 1/1
+    +-----------------------------------+
+    | DAY_OF_WEEK(DATE('2020-08-26'))   |
+    |-----------------------------------|
+    | 4                                 |
+    +-----------------------------------+
+
+    os> SELECT DAY_OF_WEEK(DATETIME('2020-08-26 00:00:00'))
+    fetched rows / total rows = 1/1
+    +------------------------------------------------+
+    | DAY_OF_WEEK(DATETIME('2020-08-26 00:00:00'))   |
+    |------------------------------------------------|
+    | 4                                              |
+    +------------------------------------------------+
+
+    os> SELECT DAY_OF_WEEK(TIMESTAMP('2020-08-26 00:00:00'))
+    fetched rows / total rows = 1/1
+    +-------------------------------------------------+
+    | DAY_OF_WEEK(TIMESTAMP('2020-08-26 00:00:00'))   |
+    |-------------------------------------------------|
+    | 4                                               |
+    +-------------------------------------------------+
+
+
 
 
 DAYOFYEAR

integ-test/src/test/java/org/opensearch/sql/sql/DateTimeFunctionIT.java

@@ -217,6 +217,49 @@ public void testDayOfWeek() throws IOException {
     verifyDataRows(result, rows(4));
   }
 
+  @Test
+  public void testDayOfWeekWithUnderscores() throws IOException {
+    JSONObject result = executeQuery("select day_of_week(date('2020-09-16'))");
+    verifySchema(result, schema("day_of_week(date('2020-09-16'))", null, "integer"));
+    verifyDataRows(result, rows(4));
+
+    result = executeQuery("select day_of_week('2020-09-16')");
+    verifySchema(result, schema("day_of_week('2020-09-16')", null, "integer"));
+    verifyDataRows(result, rows(4));
+  }
+
+  @Test
+  public void testDayOfWeekAliasesReturnTheSameResults() throws IOException {
+    JSONObject result1 = executeQuery("SELECT dayofweek(date('2022-11-22'))");
+    JSONObject result2 = executeQuery("SELECT day_of_week(date('2022-11-22'))");
+    verifyDataRows(result1, rows(3));
+    result1.getJSONArray("datarows").similar(result2.getJSONArray("datarows"));
+
+    result1 = executeQuery(String.format(
+        "SELECT dayofweek(CAST(date0 AS date)) FROM %s", TEST_INDEX_CALCS));
+    result2 = executeQuery(String.format(
+        "SELECT day_of_week(CAST(date0 AS date)) FROM %s", TEST_INDEX_CALCS));
+    result1.getJSONArray("datarows").similar(result2.getJSONArray("datarows"));
+
+    result1 = executeQuery(String.format(
+        "SELECT dayofweek(datetime(CAST(time0 AS STRING))) FROM %s", TEST_INDEX_CALCS));
+    result2 = executeQuery(String.format(
+        "SELECT day_of_week(datetime(CAST(time0 AS STRING))) FROM %s", TEST_INDEX_CALCS));
+    result1.getJSONArray("datarows").similar(result2.getJSONArray("datarows"));
+
+    result1 = executeQuery(String.format(
+        "SELECT dayofweek(CAST(time0 AS STRING)) FROM %s", TEST_INDEX_CALCS));
+    result2 = executeQuery(String.format(
+        "SELECT day_of_week(CAST(time0 AS STRING)) FROM %s", TEST_INDEX_CALCS));
+    result1.getJSONArray("datarows").similar(result2.getJSONArray("datarows"));
+
+    result1 = executeQuery(String.format(
+        "SELECT dayofweek(CAST(datetime0 AS timestamp)) FROM %s", TEST_INDEX_CALCS));
+    result2 = executeQuery(String.format(
+        "SELECT day_of_week(CAST(datetime0 AS timestamp)) FROM %s", TEST_INDEX_CALCS));
+    result1.getJSONArray("datarows").similar(result2.getJSONArray("datarows"));
+  }
+
   @Test
   public void testDayOfYear() throws IOException {
     JSONObject result = executeQuery("select dayofyear(date('2020-09-16'))");

sql/src/main/antlr/OpenSearchSQLParser.g4

@@ -244,6 +244,7 @@ datetimeConstantLiteral
     : CURRENT_DATE
     | CURRENT_TIME
     | CURRENT_TIMESTAMP
+    | DAY_OF_WEEK
     | DAY_OF_YEAR
     | LOCALTIME
     | LOCALTIMESTAMP

sql/src/test/java/org/opensearch/sql/sql/antlr/SQLSyntaxParserTest.java

@@ -197,6 +197,12 @@ public void can_parse_week_of_year_functions() {
     assertNotNull(parser.parse("SELECT week_of_year('2022-11-18')"));
   }
 
+  @Test
+  public void can_parse_day_of_week_functions() {
+    assertNotNull(parser.parse("SELECT dayofweek('2022-11-18')"));
+    assertNotNull(parser.parse("SELECT day_of_week('2022-11-18')"));
+  }
+
   @Test
   public void can_parse_dayofyear_functions() {
     assertNotNull(parser.parse("SELECT dayofyear('2022-11-18')"));