如何检查记录是否存在

Question

我希望能够检查数据库中是否存在带有特定“ ID”的记录，如果不存在则创建一个记录（即，不存在），就像这样...我也想获取“ Num”更新后的特定记录。

import sqlite3 as lite

db = lite.connect("test.db")
id_to_be_added = "123456789101112"

db.execute("CREATE TABLE USERS (ID TEXT, NUM INT)")

Query = "{ SOMETHING IN SQL }"  # This returns either True or False
if Query:
    db.execute("UPDATE USERS SET NUM = NUM + 1 WHERE ID =  {};".format(id_to_be_added))

else:
    db.execute("INSERT INTO USERS ({}, 0)".format(id_to_be_added))

num_to_be_printed = db.execute("SELECT NUM FROM USERS WHERE ID = {}".format(id_to_be_added))

print("{0} has {1}").format(id_to_be_added, num_to_be_printed)

Answer 1

创建主键并使用INSERT OR REPLACE查询，或使用SELECT查询。

Answer 2

我能够使用cur.fetchall（）解决它

import sqlite3 as lite

db = lite.connect(r"test.db")
id_tba = r"123456789101112"
cur = db.cursor()
cur.execute("SELECT * FROM USERS WHERE ID = {}".format(id_tba))

if len(cur.fetchall()) > 0:
    db.execute("UPDATE USERS SET NUM = NUM + 1 WHERE ID =  {};".format(id_tba))
else:
    db.execute("INSERT INTO USERS ({}, 0)".format(id_tba))

num_to_be_printed = db.execute("SELECT NUM FROM USERS WHERE ID = {}".format(id_tba))
print("{0} has {1}").format(id_tba, num_to_be_printed)