相同id状态变化时，去掉重复值

-- 使用窗口函数ROW_NUMBER()为每个ID的状态变化分配一个序号
WITH RankedChanges AS (
    SELECT id, status, timestamp,
           ROW_NUMBER() OVER (PARTITION BY id ORDER BY timestamp DESC) AS rn
    FROM status_changes
)
-- 选择序号为1的记录，即最新的状态变化
SELECT id, status, timestamp
FROM RankedChanges
WHERE rn = 1;

from collections import defaultdict

changes = [
    {'id': 1, 'status': 'active', 'timestamp': '2023-04-01T10:00:00'},
    {'id': 1, 'status': 'active', 'timestamp': '2023-04-01T10:00:00'},  # 重复
    {'id': 2, 'status': 'inactive', 'timestamp': '2023-04-01T11:00:00'},
]

# 使用defaultdict按ID分组，并保留最新的状态变化
latest_changes = defaultdict(lambda: {'status': None, 'timestamp': None})
for change in changes:
    if latest_changes[change['id']]['timestamp'] < change['timestamp']:
        latest_changes[change['id']] = change

# 提取最终结果
result = list(latest_changes.values())
print(result)