Python 在pymysql中选择查询
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Select query in pymysql
提问by Jasmine078
When executing the following:
执行以下操作时：
import pymysql
db = pymysql.connect(host='localhost', port=3306, user='root')
cur = db.cursor()
print(cur.execute("SELECT ParentGuardianID FROM ParentGuardianInformation WHERE UserID ='" + UserID + "'"))
The output is1
输出是1
How could I alter the code so that the actual value of the ParentGuardianID (which is '001') is printed as opposed to 1.
我如何更改代码以便打印 ParentGuardianID（即“001”）的实际值而不是1.
I'm sure the answer is simple but I am a beginner so any help would be much appreciated - thanks!
我确定答案很简单，但我是初学者，因此非常感谢您的帮助 - 谢谢！
采纳答案by Daniel Roseman
cur.execute()just returns the number of rows affected. You should do cur.fetchone()to get the actual result, or cur.fetchall()if you are expecting multiple rows.
cur.execute()只返回受影响的行数。您应该这样做cur.fetchone()以获得实际结果，或者cur.fetchall()如果您期望多行。
回答by Guillermo Luque
The cursor.execute()method gives out a cursor related to the result of the SQL sentence. In case of a selectquery, it returns the rows (if any) that meet it. So, you can iterate over these rows using a forloop for instance. In addition, I would recommend you to use pymysql.cursors.DictCursorbecause it allows treating the query results as a dictionary.
该cursor.execute()方法给出与 SQL 语句结果相关的游标。在select查询的情况下，它返回满足它的行（如果有）。因此，您可以使用for循环遍历这些行。此外，我建议您使用，pymysql.cursors.DictCursor因为它允许将查询结果视为字典。
import pymysql
db = pymysql.connect(host='localhost', port=3306, user='root')
cur = db.cursor(pymysql.cursors.DictCursor)
UserId = 'whatsoever'
sql = "SELECT ParentGuardianID FROM ParentGuardianInformation WHERE UserID ='%s'"
cur.execute(sql % UserId)
for row in cur:
print(row['ParentGuardianID'])
Good luck!
祝你好运！
