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select @@version;
| (No column name) |
|---|
| Microsoft SQL Server 2019 (RTM-CU16) (KB5011644) - 15.0.4223.1 (X64) Apr 11 2022 16:24:07 Copyright (C) 2019 Microsoft Corporation Express Edition (64-bit) on Windows Server 2019 Standard 10.0 <X64> (Build 17763: ) (Hypervisor) |
CREATE table transactions (
client_id INTEGER NOT NULL,
is_cancelled TINYINT,
date DATE NOT NULL
);
INSERT INTO transactions (client_id, is_cancelled, date)
VALUES
(1, 0, '2022-01-01'),
(1, 1, '2022-01-02'),
(1, 1, '2022-01-03'),
(1, 1, '2022-01-04'),
(1, 0, '2022-01-05'),
(1, 1, '2022-01-06'),
(2, 0, '2022-01-01'),
(2, 0, '2022-01-02'),
(2, 0, '2022-01-03'),
(2, 0, '2022-01-04'),
(2, 1, '2022-01-05'),
(2, 1, '2022-01-06'),
(2, 0, '2022-01-07'),
(2, 1, '2022-01-08')
14 rows affected
WITH PrevValues AS (
SELECT
client_id,
LAG(is_cancelled) OVER (PARTITION BY client_id ORDER BY date) AS previous_cancelled,
CASE WHEN is_cancelled = LAG(is_cancelled) OVER (PARTITION BY client_id ORDER BY date)
THEN NULL ELSE 1 END
as is_different,
date,
is_cancelled
FROM transactions
),
Grouped AS (
SELECT
client_id,
date,
is_different,
COUNT(is_different) OVER (PARTITION BY client_id ORDER BY date ROWS UNBOUNDED PRECEDING) AS group_id
FROM PrevValues
),
ByGroups AS (
SELECT
client_id,
COUNT(*) as in_a_row
FROM Grouped
GROUP BY
client_id,
group_id
HAVING COUNT(*) >= 3
)
SELECT
client_id,
MAX(in_a_row) as max_in_a_row,
MIN(in_a_row) as min_in_a_row,
COUNT(*) as num_groups
FROM ByGroups
GROUP BY
| client_id | max_in_a_row | min_in_a_row | num_groups |
|---|---|---|---|
| 1 | 3 | 3 | 1 |
| 2 | 4 | 4 | 1 |
Warning: Null value is eliminated by an aggregate or other SET operation.