Create an overload for com.snowflake.snowpark.functions.sum (#84)

* Create an overload for com.snowflake.snowpark.functions.sum

* Update comments and rename param

* Fix comments

src/main/java/com/snowflake/snowpark_java/Functions.java

@@ -360,8 +360,7 @@ public static Column stddev_pop(Column col) {
   }
 
   /**
-   * Returns the sum of non-NULL records in a group. You can use the DISTINCT keyword to compute the
-   * sum of unique non-null values. If all records inside a group are NULL, the function returns
+   * Returns the sum of non-NULL records in a group. If all records inside a group are NULL, the function returns
    * NULL.
    *
    * @since 0.9.0
@@ -372,6 +371,16 @@ public static Column sum(Column col) {
     return new Column(com.snowflake.snowpark.functions.sum(col.toScalaColumn()));
   }
 
+  /**
+   * Returns the sum of non-NULL records in a group. If all records inside a group are NULL, the function returns
+   * NULL.
+   *
+   * @since 1.12.0
+   * @param colName The input column name
+   * @return The result column
+   */
+  public static Column sum(String colName) { return sum(col(colName)); }
+
   /**
    * Returns the sum of non-NULL distinct records in a group. You can use the DISTINCT keyword to
    * compute the sum of unique non-null values. If all records inside a group are NULL, the function

src/main/scala/com/snowflake/snowpark/functions.scala

@@ -348,15 +348,25 @@ object functions {
   def stddev_pop(e: Column): Column = builtin("stddev_pop")(e)
 
   /**
-   * Returns the sum of non-NULL records in a group. You can use the DISTINCT keyword to compute
-   * the sum of unique non-null values. If all records inside a group are NULL,
+   * Returns the sum of non-NULL records in a group. If all records inside a group are NULL,
    * the function returns NULL.
    *
    * @group agg_func
    * @since 0.1.0
    */
   def sum(e: Column): Column = builtin("sum")(e)
 
+  /**
+   * Returns the sum of non-NULL records in a group. If all records inside a group are NULL,
+   * the function returns NULL.
+   *
+   * @group agg_func
+   * @since 1.12.0
+   * @param colName The input column name
+   * @return The result column
+   */
+  def sum(colName: String): Column = sum(col(colName))
+
   /**
    * Returns the sum of non-NULL distinct records in a group. You can use the DISTINCT keyword to
    * compute the sum of unique non-null values. If all records inside a group are NULL,

src/test/java/com/snowflake/snowpark_test/JavaFunctionSuite.java

@@ -195,6 +195,8 @@ public void sum() {
 
     checkAnswer(df.groupBy(df.col("a")).agg(Functions.sum(df.col("a"))), expected, false);
 
+    checkAnswer(df.groupBy(df.col("a")).agg(Functions.sum("a")), expected, false);
+
     Row[] expected1 = {Row.create(3, 3), Row.create(2, 2), Row.create(1, 1)};
     checkAnswer(df.groupBy(df.col("a")).agg(Functions.sum_distinct(df.col("a"))), expected1, false);
   }

src/test/scala/com/snowflake/snowpark_test/FunctionSuite.scala

@@ -99,6 +99,11 @@ trait FunctionSuite extends TestData {
       Seq(Row(3, 6), Row(2, 4), Row(1, 1)),
       sort = false)
 
+    checkAnswer(
+      duplicatedNumbers.groupBy("A").agg(sum("A")),
+      Seq(Row(3, 6), Row(2, 4), Row(1, 1)),
+      sort = false)
+
     checkAnswer(
       duplicatedNumbers.groupBy("A").agg(sum_distinct(col("A"))),
       Seq(Row(3, 3), Row(2, 2), Row(1, 1)),