Aggregation functions
AVG¶
Since: 0.6.0
1 | |
Stream, Table
Return the average value for a given column.
COLLECT_LIST¶
Since: -
1 | |
Stream, Table
Return an array containing all the values of col1 from each
input row (for the specified grouping and time window, if any).
Currently only works for simple types (not Map, Array, or Struct).
The size of the result Array can be limited to a maximum of
ksql.functions.collect_list.limit entries and any values beyond this
limit are silently ignored.
When using with a window type of session, it can sometimes
happen that two session windows get merged together into one when a
out-of-order record with a timestamp between the two windows is
processed. In this case, the record limit is calculated by
first considering all the records from the first window, then the
out-of-order record, then the records from the second window in
the order they were originally processed.
COLLECT_SET¶
Since: -
1 | |
Stream
Return an array containing the distinct values of col1 from
each input row (for the specified grouping and time window, if any).
Currently only works for simple types (not Map, Array, or Struct).
The size of the result Array can be limited to a maximum of
ksql.functions.collect_set.limit entries and any values beyond this
limit are silently ignored.
When using with a window type of session, it can sometimes
happen that two session windows get merged together into one when a
out-of-order record with a timestamp between the two windows is
processed. In this case, the record limit is calculated by
first considering all the records from the first window, then the
out-of-order record, then the records from the second window in
the order they were originally processed.
COUNT¶
Since: -
1 | |
1 | |
Stream, Table
Count the number of rows. When col1 is specified, the count
returned will be the number of rows where col1 is non-null.
When * is specified, the count returned will be the total
number of rows.
COUNT_DISTINCT¶
Since: 0.7.0
1 | |
Stream, Table
Returns the approximate number of unique values of col1 in a group.
The function implementation uses HyperLogLog
to estimate cardinalities of 10^9 with a typical standard error of 2%.
EARLIEST_BY_OFFSET¶
Since: 0.10.0
1 | |
Stream
Return the earliest value for the specified column. The earliest value in the partition
has the lowest offset.
The optional ignoreNulls parameter, available since version 0.13.0, controls whether nulls are ignored. The default
is to ignore null values.
Since: 0.13.0
1 | |
Stream
Return the earliest N values for the specified column as an ARRAY. The earliest values
in the partition have the lowest offsets.
The optional ignoreNulls parameter controls whether nulls are ignored. The default
is to ignore null values.
HISTOGRAM¶
Since: -
1 | |
Stream, Table
Return a map containing the distinct String values of col1
mapped to the number of times each one occurs for the given window.
This version limits the number of distinct values which can be
counted to 1000, beyond which any additional entries are ignored.
When using with a window type of session, it can sometimes
happen that two session windows get merged together into one when a
out-of-order record with a timestamp between the two windows is
processed. In this case the 1000 record limit is calculated by
first considering all the records from the first window, then the
out-of-order record, then the records from the second window in
the order they were originally processed.
LATEST_BY_OFFSET¶
Since: 0.8.0
1 | |
Stream
Return the latest value for the specified column. The latest value in the partition
has the largest offset.
The optional ignoreNulls parameter, available since version 0.13.0, controls whether nulls are ignored. The default
is to ignore null values.
Since: 0.13.0
1 | |
Stream
Returns the latest N values for the specified column as an ARRAY. The latest values have
the largest offset.
The optional ignoreNulls parameter controls whether nulls are ignored. The default is to ignore
null values.
MAX¶
Since: -
1 | |
Stream
Return the maximum value for a given column and window.
Rows that have col1 set to null are ignored.
MIN¶
Since: -
1 | |
Stream
Return the minimum value for a given column and window.
Rows that have col1 set to null are ignored.
STDDEV_SAMP¶
Since: - 0.16.0
1 | |
Stream, Table
Returns the sample standard deviation for the column.
SUM¶
Since: -
1 | |
Stream, Table
Sums the column values.
Rows that have col1 set to null are ignored.
TOPK¶
Since: -
1 | |
Stream
Return the Top K values for the given column and window
Rows that have col1 set to null are ignored.
TOPKDISTINCT¶
Since: -
1 | |
Stream
Return the distinct Top K values for the given column and window
Rows that have col1 set to null are ignored.