import pandas as pd

# 创建数据帧
df = pd.DataFrame({'A': [1, 2, 3, 4, 5],
                   'B': [10, 20, 30, 40, 50]})

# 根据单个条件查询
result = df.loc[df['A'] > 3]
print(result)

result = df.loc[(df['A'] > 2) & (df['B'] < 40)]
print(result)

result = df.loc[(df['A'] > 2) | (df['B'] < 40)]
print(result)

result = df.loc[df['A'] > 3, ['B']]
print(result)

from pandasql import sqldf
print("select")
query1 = "select * from df where A>2 and B<40"
queryresult = sqldf(query1)
print(queryresult)