* 用例1： 分析特定期货合约的价格趋势
```
import dai
df = dai.query("""
SELECT
date, instrument, close * adjust_factor AS adjusted_close
FROM cn_future_bar1d_adjust
WHERE instrument = 'AP9999.CZC'
ORDER BY date""",
filters={"date": ["2023-01-01", "2023-12-31"]}
).df()
```
* 用例2：计算某品种在一个月内的平均持仓量
```
import dai
df = dai.query("""
SELECT
instrument, AVG(open_interest) AS average_open_interest
FROM cn_future_bar1d_adjust
WHERE product_code = 'AP'
GROUP BY instrument""",
filters={"date": ["2023-01-01", "2023-01-31"]}
).df()
```
* 用例3：使用前复权数据追踪某合约在特定时间范围内是否突破了涨跌停限制
```
import dai
df = dai.query("""
SELECT
date, instrument, close, upper_limit, lower_limit
FROM cn_future_bar1d_adjust
WHERE (close >= upper_limit OR close <= lower_limit)""",
filters={"date": ["2023-01-01", "2023-01-31"]}
).df()
```