* 用例1：查询特定日期各行业的涨跌幅
```
import dai
df = dai.query("""
SELECT
date, instrument, change_ratio
FROM cn_stock_industry_sw_bar1d
ORDER BY change_ratio DESC""",
filters={"date": ["2023-06-01"]}
).df()
```
* 用例2：分析给定时间段内，各行业的平均涨跌幅
```
import dai
df = dai.query("""
SELECT
instrument, AVG(change_ratio) as avg_change_ratio
FROM cn_stock_industry_sw_bar1d
GROUP BY instrument
ORDER BY avg_change_ratio DESC""",
filters={"date": ["2023-01-01", "2023-12-31"]}
).df()
```
* 用例3：利用高价和低价的差异分析行业在特定日期的市场波动性
```
import dai
df = dai.query("""
SELECT
date, instrument, high - low as price_range
FROM cn_stock_industry_sw_bar1d
ORDER BY price_range DESC""",
filters={"date": ["2023-06-01"]}
).df()
```