问题描述
我正在尝试使用一个我几乎不知道的数据库，我需要知道表的列名：
这是我尝试过的：
client = DataFrameClient(host,8086,username,password,"marketdata")
client.switch_database('marketdata')
print(client.query("show measurements"))
# ResultSet({'('measurements',None)': [{'name': 'bookTicker'}]})
query = "SELECT COUNT(disTINCT bookTicker) FROM @R_493_4045@ion_schema.columns WHERE table_schema = 'marketdata'"
dataframes = client.query(query)
raise InfluxDBClientError(self.error)
influxdb.exceptions.InfluxDBClientError: retention policy not found: @R_493_4045@ion_schema
我也试过：
query = "select * from bookTicker limit 10"
raise ChunkedEncodingError(e)
requests.exceptions.ChunkedEncodingError: ("Connection broken: InvalidChunkLength(got length b'',0 bytes read)",InvalidChunkLength(got length b'',0 bytes read))
解决方法
您正在尝试将 num2find = int(input("Enter a number to find: "))
found = False # rename flag
with open("testfile.txt") as test_file: # use with to avoid missing closing the file
for line in test_file: # use a for loop to iterate over each line in the file
num = int(line)
if num == num2find:
found = True
break
if found: # print results at the end once file was processed
print("Number found.")
else:
print("Number not found.")
知识用于非 SQL InfluxDB。
SQL 没有列的概念，但有标签（在 SQL 中的意思是索引列之类的东西）和字段（类似于列的东西）。
您可以通过查询探索它们：
SHOW TAG KEYS [ON
https://docs.influxdata.com/influxdb/v1.7/query_language/schema_exploration/#show-tag-keys
显示字段键 [ON
https://docs.influxdata.com/influxdb/v1.7/query_language/schema_exploration/#show-field-keys