Upsolver
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LAST_K
The last "k" values per group.

Syntax

LAST_K(VALUE, [K])

Arguments

VALUE: An expression of any type. K: An optional integer (default is 1). ‌

Returns

The result type matches VALUE for each key.

Notes

In Upsolver output, the LAST_K function needs no TYPE field.

Example

Data

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[
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{
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"GROUP_ID":"G1",
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"USER_ID":"U1",
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"CONNECTION_TIME":"2020-06-26 02:31:29,573"
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},
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{
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"GROUP_ID":"G1",
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"USER_ID":"U2",
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"CONNECTION_TIME":"2020-06-26 18:11:45,783"
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},
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{
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"GROUP_ID":"G2",
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"USER_ID":"Z1",
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"CONNECTION_TIME":"2020-06-26 23:54:27,687"
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},
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{
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"GROUP_ID":"G2",
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"CONNECTION_TIME":"2020-07-26 23:54:27,687"
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},
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{
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"GROUP_ID":"G1",
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"USER_ID":"U2",
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"CONNECTION_TIME":"2021-07-01 02:31:29,573"
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},
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{
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"GROUP_ID":"G1",
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"USER_ID":"U1",
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"CONNECTION_TIME":"2021-07-01 18:11:45,783"
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},
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{
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"GROUP_ID":"G2",
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"USER_ID":"Z1",
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"CONNECTION_TIME":"2021-07-01 23:54:27,687"
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}
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]
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Query:

List the last two connection times by user group:
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SET
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DATE_TIME = TO_DATE(data.CONNECTION_TIME);
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SELECT
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data.GROUP_ID AS group_id:STRING,
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LAST_K(2, data.CONNECTION_TIME) AS last_k_data_connection_time:STRING
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FROM
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"SAMPLE_DATA_G1U1 - json"
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GROUP BY
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data.GROUP_ID
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Results:

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{
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"last_k_data_connection_time":[
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"2020-07-26 23:54:27,687",
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"2021-07-01 23:54:27,687"
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],
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"group_id":"G2"
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}{
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"last_k_data_connection_time":[
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"2021-07-01 02:31:29,573",
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"2021-07-01 18:11:45,783"
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],
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"group_id":"G1"
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}
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