蟒蛇疊代SQL查詢select語句

Question

我如何執行SELECT語句對所有的4名ID的是10，20，34和1所期望的結果是在一個列表

import pymysql 
import json 

conn = pymysql.connect(host='localhost', port=3306, user='root', passwd='', 
db='mydb', charset='utf8mb4', cursorclass=pymysql.cursors.DictCursor) 

cursor = conn.cursor() 

select_query = "select * from users where id = " 
ids = ["10", "20", "34", "1"] 
for x in ids: 
    var = select_query + x 
    # print(var) 
    print(list(cursor.execute(var))) 

Answer 1

按照PyMySQL docs，該cursor.execute()函數返回一個int，這就是爲什麼你的錯誤被顯示出來。你要調用，然後使用fetch functions的一個實際返回的結果

import pymysql 

conn = pymysql.connect(host='localhost', port=3306, user='root', passwd='', 
         db='mydb', charset='utf8mb4', cursorclass=pymysql.cursors.DictCursor) 

cursor = conn.cursor() 

select_query = "select * from users where id = " 
ids = ["10", "20", "34", "1"] 
for x in ids: 
    var = select_query + x 
    # print(var) 
    cursor.execute(var) 
    print(list(cursor.fetchall())) 

或者，如果你希望所有的結果在一個列表中：

import pymysql 

conn = pymysql.connect(host='localhost', port=3306, user='root', passwd='', 
         db='mydb', charset='utf8mb4', cursorclass=pymysql.cursors.DictCursor) 

cursor = conn.cursor() 

lst = [] 

select_query = "select * from users where id = " 
ids = ["10", "20", "34", "1"] 
for x in ids: 
    var = select_query + x 
    # print(var) 
    cursor.execute(var) 
    lst.extend(cursor.fetchall()) 

print(lst) 

或字典

import pymysql 

conn = pymysql.connect(host='localhost', port=3306, user='root', passwd='', 
         db='mydb', charset='utf8mb4', cursorclass=pymysql.cursors.DictCursor) 

cursor = conn.cursor() 

results = {} 

select_query = "select * from users where id = " 
ids = ["10", "20", "34", "1"] 
for x in ids: 
    var = select_query + x 
    # print(var) 
    cursor.execute(var) 
    results[x] = list(cursor.fetchall()) 

print(results) 

Answer 2

你可能忘了強制轉換X爲str

import pymysql 
import json 

conn = pymysql.connect(host='localhost', port=3306, user='root', passwd='', 
db='mydb', charset='utf8mb4', cursorclass=pymysql.cursors.DictCursor) 

cursor = conn.cursor() 

select_query = "select * from users where id = " 
ids = ["10", "20", "34", "1"] 
for x in ids: 
    var = select_query + str(x) # here 
    # print(var) 
    print(list(cursor.execute(var)))