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Returns a sort expression based on the descending order of the given column name, and null values appear after non-null values. Supports Spark Connect.
Syntax
from pyspark.databricks.sql import functions as dbf
dbf.desc_nulls_last(col=<col>)
Parameters
| Parameter | Type | Description |
|---|---|---|
col |
pyspark.sql.Column or str |
Target column to sort by in the descending order. |
Returns
pyspark.sql.Column: the column specifying the order.
Examples
Example 1: Sorting a DataFrame with null values in descending order.
from pyspark.databricks.sql import functions as dbf
df = spark.createDataFrame([(0, None), (1, "Bob"), (2, "Alice")], ["age", "name"])
df.sort(dbf.desc_nulls_last(df.name)).show()
+---+-----+
|age| name|
+---+-----+
| 1| Bob|
| 2|Alice|
| 0| NULL|
+---+-----+
Example 2: Sorting a DataFrame with null values in descending order using column name string.
from pyspark.databricks.sql import functions as dbf
df = spark.createDataFrame([(0, None), (1, "Bob"), (2, "Alice")], ["age", "name"])
df.sort(dbf.desc_nulls_last("name")).show()
+---+-----+
|age| name|
+---+-----+
| 1| Bob|
| 2|Alice|
| 0| NULL|
+---+-----+