Python - 代码中的多个 SQL 查询

Question

我正在创建一个接收输入（13 位数字）的 Python 脚本。然后获取该号码并检查它是否在我的数据库中（以检查此人是否已注册）。之后，它需要检查那个人是否登录（在我的数据库中，我有一个名为“状态”的列，它是 0 或 1）。在我的一生中，我无法弄清楚如何在我的代码中执行第二个查询。

我正在使用带有 MySQLdb 模块的 Python 2.7。

请参阅下面的代码：

导入 MySQL 数据库

# Create a database connection
db = MySQLdb.connect(host="******", user="******", passwd="*****", db="******")
cur = db.cursor()

# Create a query to select all IDs
cur.execute("SELECT id, FROM users")
clientArray = []

# Loop over all IDs returned from query,
# save all IDs in the clientArray
for row in cur.fetchall():
    clientID = str(row[0])
    clientArray.append(clientID)
print clientArray #Printing for troubleshooting, ignore this


# Loop infinitely until - when you receive an input (which will be the clientID)
# check if the clientID exists in the clientArray.

# If the clientID exists, check to see whether the client has already been checked in
# If the client checkin returns FALSE, check the client in - turn on a GREEN LED light
# If the client checkin returns TRUE, check the client out - turn on a RED light

# If the clientID does not exist in clientArray, turn on the RED and GREEN LED lights

clientIDInput = ""
while True:
    clientIDInput = raw_input("")
    if clientIDInput in clientArray:
        print "The ID has been found in the database"
        # Check to see whether the person has been logged in or not

        ### THIS CODE DOES NOT WORK, CAN'T FIGURE THIS PART OUT ###
        cur.execute("SELECT status FROM users WHERE id='clientIDInput'")
        clientStatus = cur.fetchall()
        if clientStatus == True:
            print "This person is already checked in. Checking out now." 
            # Update MySQL database and change status from 1 to 0
        if clientStatus == False:
            print "This person has not checked in yet. Checking in now."
            # Update MySQL database and change status from 0 to 1        
    else:
        print " The ID has not been found in the database"

Answer 1

您需要参数化查询并将clientIDInput 变量值传递给它。然后，使用fetchone() 得到结果：

cur.execute("SELECT status FROM users WHERE id=%s", (clientIDInput, ))
data = cur.fetchone()
if not data:
    print "The ID has not been found in the database"
else:
    status = data[0]
    if status:
        print "This person is already checked in. Checking out now." 
        # Update MySQL database and change status from 1 to 0
    else:
        print "This person has not checked in yet. Checking in now."

希望我正确理解了用例和逻辑。

Answer 2

您不能直接将 'clientIDInput' 放入查询中。

你需要这样做：

  cur.execute("SELECT status FROM users WHERE id='" + clientIDInput + "'")