如何确定一列中的日期是否唯一？

SELECT DATE(your_date_column) AS date, COUNT(*)
FROM your_table
GROUP BY DATE(your_date_column)
HAVING COUNT(*) > 1;

import pandas as pd

# 假设df是你的DataFrame，'date_column'是日期列的名称
df['date_column'] = pd.to_datetime(df['date_column'])  # 确保日期列是datetime类型
duplicates = df[df.duplicated(subset=['date_column'], keep=False)]

if not duplicates.empty:
    print("存在重复的日期：")
    print(duplicates['date_column'].unique())
else:
    print("所有日期都是唯一的。")

const { MongoClient } = require('mongodb');  // 假设使用MongoDB

async function checkUniqueDates() {
    const uri = "your_mongodb_connection_string";
    const client = new MongoClient(uri, { useNewUrlParser: true, useUnifiedTopology: true });

    try {
        await client.connect();
        const database = client.db('your_database_name');
        const collection = database.collection('your_collection_name');

        const dates = await collection.distinct('date_column');
        const dateCounts = await collection.aggregate([
            { $group: { _id: '$date_column', count: { $sum: 1 } } },
            { $match: { count: { $gt: 1 } } }
        ]).toArray();

        if (dateCounts.length > 0) {
            console.log("存在重复的日期：");
            dateCounts.forEach(date => console.log(date._id));
        } else {
            console.log("所有日期都是唯一的。");
        }
    } finally {
        await client.close();
    }
}

checkUniqueDates().catch(console.dir);