public class Window
extends Object
// PARTITION BY country ORDER BY date ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
Window.partitionBy("country").orderBy("date")
.rowsBetween(Window.unboundedPreceding, Window.currentRow)
// PARTITION BY country ORDER BY date ROWS BETWEEN 3 PRECEDING AND 3 FOLLOWING
Window.partitionBy("country").orderBy("date").rowsBetween(-3, 3)
Constructor and Description |
---|
Window() |
Modifier and Type | Method and Description |
---|---|
static long |
currentRow()
Value representing the current row.
|
static WindowSpec |
orderBy(Column... cols)
Creates a
WindowSpec with the ordering defined. |
static WindowSpec |
orderBy(scala.collection.Seq<Column> cols)
Creates a
WindowSpec with the ordering defined. |
static WindowSpec |
orderBy(String colName,
scala.collection.Seq<String> colNames)
Creates a
WindowSpec with the ordering defined. |
static WindowSpec |
orderBy(String colName,
String... colNames)
Creates a
WindowSpec with the ordering defined. |
static WindowSpec |
partitionBy(Column... cols)
Creates a
WindowSpec with the partitioning defined. |
static WindowSpec |
partitionBy(scala.collection.Seq<Column> cols)
Creates a
WindowSpec with the partitioning defined. |
static WindowSpec |
partitionBy(String colName,
scala.collection.Seq<String> colNames)
Creates a
WindowSpec with the partitioning defined. |
static WindowSpec |
partitionBy(String colName,
String... colNames)
Creates a
WindowSpec with the partitioning defined. |
static WindowSpec |
rangeBetween(long start,
long end)
|
static WindowSpec |
rowsBetween(long start,
long end)
|
static long |
unboundedFollowing()
Value representing the last row in the partition, equivalent to "UNBOUNDED FOLLOWING" in SQL.
|
static long |
unboundedPreceding()
Value representing the first row in the partition, equivalent to "UNBOUNDED PRECEDING" in SQL.
|
public static WindowSpec partitionBy(String colName, String... colNames)
WindowSpec
with the partitioning defined.colName
- (undocumented)colNames
- (undocumented)public static WindowSpec partitionBy(Column... cols)
WindowSpec
with the partitioning defined.cols
- (undocumented)public static WindowSpec orderBy(String colName, String... colNames)
WindowSpec
with the ordering defined.colName
- (undocumented)colNames
- (undocumented)public static WindowSpec orderBy(Column... cols)
WindowSpec
with the ordering defined.cols
- (undocumented)public static WindowSpec partitionBy(String colName, scala.collection.Seq<String> colNames)
WindowSpec
with the partitioning defined.colName
- (undocumented)colNames
- (undocumented)public static WindowSpec partitionBy(scala.collection.Seq<Column> cols)
WindowSpec
with the partitioning defined.cols
- (undocumented)public static WindowSpec orderBy(String colName, scala.collection.Seq<String> colNames)
WindowSpec
with the ordering defined.colName
- (undocumented)colNames
- (undocumented)public static WindowSpec orderBy(scala.collection.Seq<Column> cols)
WindowSpec
with the ordering defined.cols
- (undocumented)public static long unboundedPreceding()
Window.rowsBetween(Window.unboundedPreceding, Window.currentRow)
public static long unboundedFollowing()
Window.rowsBetween(Window.unboundedPreceding, Window.unboundedFollowing)
public static long currentRow()
Window.rowsBetween(Window.unboundedPreceding, Window.currentRow)
public static WindowSpec rowsBetween(long start, long end)
WindowSpec
with the frame boundaries defined,
from start
(inclusive) to end
(inclusive).
Both start
and end
are positions relative to the current row. For example, "0" means
"current row", while "-1" means the row before the current row, and "5" means the fifth row
after the current row.
We recommend users use Window.unboundedPreceding
, Window.unboundedFollowing
,
and Window.currentRow
to specify special boundary values, rather than using integral
values directly.
A row based boundary is based on the position of the row within the partition. An offset indicates the number of rows above or below the current row, the frame for the current row starts or ends. For instance, given a row based sliding frame with a lower bound offset of -1 and a upper bound offset of +2. The frame for row with index 5 would range from index 4 to index 7.
import org.apache.spark.sql.expressions.Window
val df = Seq((1, "a"), (1, "a"), (2, "a"), (1, "b"), (2, "b"), (3, "b"))
.toDF("id", "category")
val byCategoryOrderedById =
Window.partitionBy($"category").orderBy($"id").rowsBetween(Window.currentRow, 1)
df.withColumn("sum", sum($"id") over byCategoryOrderedById).show()
+---+--------+---+
| id|category|sum|
+---+--------+---+
| 1| b| 3|
| 2| b| 5|
| 3| b| 3|
| 1| a| 2|
| 1| a| 3|
| 2| a| 2|
+---+--------+---+
start
- boundary start, inclusive. The frame is unbounded if this is
the minimum long value (Window.unboundedPreceding
).end
- boundary end, inclusive. The frame is unbounded if this is the
maximum long value (Window.unboundedFollowing
).public static WindowSpec rangeBetween(long start, long end)
WindowSpec
with the frame boundaries defined,
from start
(inclusive) to end
(inclusive).
Both start
and end
are relative to the current row. For example, "0" means "current row",
while "-1" means one off before the current row, and "5" means the five off after the
current row.
We recommend users use Window.unboundedPreceding
, Window.unboundedFollowing
,
and Window.currentRow
to specify special boundary values, rather than using long values
directly.
A range-based boundary is based on the actual value of the ORDER BY expression(s). An offset is used to alter the value of the ORDER BY expression, for instance if the current ORDER BY expression has a value of 10 and the lower bound offset is -3, the resulting lower bound for the current row will be 10 - 3 = 7. This however puts a number of constraints on the ORDER BY expressions: there can be only one expression and this expression must have a numerical data type. An exception can be made when the offset is unbounded, because no value modification is needed, in this case multiple and non-numeric ORDER BY expression are allowed.
import org.apache.spark.sql.expressions.Window
val df = Seq((1, "a"), (1, "a"), (2, "a"), (1, "b"), (2, "b"), (3, "b"))
.toDF("id", "category")
val byCategoryOrderedById =
Window.partitionBy($"category").orderBy($"id").rangeBetween(Window.currentRow, 1)
df.withColumn("sum", sum($"id") over byCategoryOrderedById).show()
+---+--------+---+
| id|category|sum|
+---+--------+---+
| 1| b| 3|
| 2| b| 5|
| 3| b| 3|
| 1| a| 4|
| 1| a| 4|
| 2| a| 2|
+---+--------+---+
start
- boundary start, inclusive. The frame is unbounded if this is
the minimum long value (Window.unboundedPreceding
).end
- boundary end, inclusive. The frame is unbounded if this is the
maximum long value (Window.unboundedFollowing
).