如何使用JSON输入构建动态SQL "WHERE“语句

import json
import psycopg2

# 假设接收到的JSON输入为：
# {
#   "conditions": [
#     {"field": "name", "operator": "LIKE", "value": "John"},
#     {"field": "age", "operator": ">=", "value": 18}
#   ]
# }

# 解析JSON输入
json_input = '''
{
  "conditions": [
    {"field": "name", "operator": "LIKE", "value": "John"},
    {"field": "age", "operator": ">=", "value": 18}
  ]
}
'''
conditions = json.loads(json_input)["conditions"]

# 构建动态SQL语句
sql = "SELECT * FROM users WHERE "
for condition in conditions:
    field = condition["field"]
    operator = condition["operator"]
    value = condition["value"]
    sql += f"{field} {operator} '{value}' AND "

# 去除最后一个多余的"AND"
sql = sql[:-5]

# 连接数据库
conn = psycopg2.connect(database="your_database", user="your_username", password="your_password", host="your_host", port="your_port")
cursor = conn.cursor()

# 执行SQL查询
cursor.execute(sql)
results = cursor.fetchall()

# 处理查询结果
for row in results:
    # 处理每一行的数据

# 关闭数据库连接
cursor.close()
conn.close()