Window aggregation

In this page, you will see how to write window aggregations in SELECT statements. See window to understand the concept around windowing in SpringQL.

Understanding on GROUP BY in standard SQL is also required, so learn a bit about it before writing SpringQL's queries.

Aggregation without grouping

Aggregation without grouping

SELECT STREAM
    <aggregate expression> [AS <alias>] 
    <, ...>*
FROM <stream name>
[FIXED | SLIDING] WINDOW <time-based width in DURATION>, <allowed latency in DURATION>;

Example (10-sec fixed window; 1-sec allowed latency)

SELECT STREAM
    AVG(source_trade.amount) AS avg_amount
FROM source_trade
FIXED WINDOW DURATION_SECS(10), DURATION_SECS(1);

Aggregation with grouping

Aggregation without grouping

SELECT STREAM
    [<aggregate expression> | <group-by key>] [AS <alias>] 
    <, ...>*
FROM <stream name>
GROUP BY <group-by key> <, ...>*
[FIXED | SLIDING] WINDOW <time-based width in DURATION>, <allowed latency in DURATION>;

Example (10-sec fixed window; 0-sec allowed latency)

SELECT STREAM
    FLOOR_TIME(source_trade.ts, DURATION_SECS(10)) AS min_ts,
    source_trade.ticker AS ticker,
    AVG(source_trade.amount) AS avg_amount
FROM source_trade
GROUP BY min_ts, ticker
FIXED WINDOW DURATION_SECS(10), DURATION_SECS(0);