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Registers a Java user-defined aggregate function as a SQL function.
Syntax
registerJavaUDAF(name, javaClassName)
Parameters
| Parameter | Type | Description |
|---|---|---|
name |
str | Name of the user-defined aggregate function. |
javaClassName |
str | Fully qualified name of the Java class. |
Returns
None
Examples
spark.udf.registerJavaUDAF("javaUDAF", "test.org.apache.spark.sql.MyDoubleAvg")
df = spark.createDataFrame([(1, "a"), (2, "b"), (3, "a")], ["id", "name"])
df.createOrReplaceTempView("df")
q = "SELECT name, javaUDAF(id) as avg from df group by name order by name desc"
spark.sql(q).collect()
# [Row(name='b', avg=102.0), Row(name='a', avg=102.0)]