使用reat查询子表，提示子表不存在

[TDuser_rGgW_6626 (李传涛)]

询子表 t_DV_A_ROBOT_L 时出错: [0x2603]: Fail to get table info, error: Table does not exist 查报错，client.sql(“use iot”)
query = f"SELECT * FROM iot.{subtable_name} ORDER BY ts DESC LIMIT 1"
result = client.sql(query)