* 用例1：查询指定日期存在的基金列表
```
import dai
df = dai.query("""
SELECT
instrument, name
FROM cn_fund_instruments""",
filters={"date": ["2023-06-01"]}
).df()
```
* 用例2：查询给定基金在特定时间段内的交易日历
```
import dai
df = dai.query("""
SELECT date
FROM cn_fund_instruments
WHERE instrument ='159001.SZ'
ORDER BY date""",
filters={"date": ['2023-01-01', '2023-12-31']},
).df()
```
* 用例3：查询最活跃（交易天数最多）的前10只基金
```
import dai
df = dai.query("""
SELECT
instrument, COUNT(*) as trading_days_count
FROM cn_fund_instruments
GROUP BY instrument
ORDER BY trading_days_count DESC
LIMIT 10
""").df()
```