versioned_docs/version-3.0/sql-manual/sql-functions/window-functions/window-function-window-funnel.md

---
{
    "title": "WINDOW_FUNCTION_WINDOW_FUNNEL",
    "language": "en"
}
---

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## WINDOW FUNCTION WINDOW_FUNNEL
### description

Searches the longest event chain happened in order (event1, event2, ... , eventN) along the timestamp_column with length of window.

- window is the length of time window in seconds.
- mode can be one of the followings:
    - "default": Defualt mode.
    - "deduplication": If the same event holds for the sequence of events, then such repeating event interrupts further processing. E.g. the array parameter is [event1='A', event2='B', event3='C', event4='D'], and the original event chain is "A-B-C-B-D". Since event B repeats, the filtered event chain can only be "A-B-C" and the max event level is 3.
    - "fixed": Don't allow interventions of other events. E.g. the array parameter is [event1='A', event2='B', event3='C', event4='D'], and the original event chain is A->B->D->C, it stops finding A->B->C at the D and the max event level is 2.
    - "increase": Apply conditions only to events with strictly increasing timestamps.
- timestamp_column specifies column of DATETIME type, sliding time window works on it.
- evnetN is boolean expression like eventID = 1004.

The function works according to the algorithm:

- The function searches for data that triggers the first condition in the chain and sets the event counter to 1. This is the moment when the sliding window starts.
- If events from the chain occur sequentially within the window, the counter is incremented. If the sequence of events is disrupted, the counter is not incremented.
- If the data has multiple event chains at varying points of completion, the function will only output the size of the longest chain.

```sql
window_funnel(window, mode, timestamp_column, event1, event2, ... , eventN)
```

### example

```sql
CREATE TABLE windowfunnel_test (
                `xwho` varchar(50) NULL COMMENT 'xwho',
                `xwhen` datetime COMMENT 'xwhen',
                `xwhat` int NULL COMMENT 'xwhat'
                )
DUPLICATE KEY(xwho)
DISTRIBUTED BY HASH(xwho) BUCKETS 3
PROPERTIES (
    "replication_num" = "1"
);

INSERT into windowfunnel_test (xwho, xwhen, xwhat) values ('1', '2022-03-12 10:41:00', 1),
                                                   ('1', '2022-03-12 13:28:02', 2),
                                                   ('1', '2022-03-12 16:15:01', 3),
                                                   ('1', '2022-03-12 19:05:04', 4);

select window_funnel(3600 * 3, 'default', t.xwhen, t.xwhat = 1, t.xwhat = 2 ) AS level from windowfunnel_test t;

| level |
|---|
| 2 |
```

### keywords

    WINDOW,FUNCTION,WINDOW_FUNNEL