There is no legal virtual currency platform in mainland China. 1. According to the notice issued by the People's Bank of China and other departments, all business activities related to virtual currency in the country are illegal; 2. Users should pay attention to the compliance and reliability of the platform, such as holding a mainstream national regulatory license, having a strong security technology and risk control system, an open and transparent operation history, a clear asset reserve certificate and a good market reputation; 3. The relationship between the user and the platform is between the service provider and the user, and based on the user agreement, it clarifies the rights and obligations of both parties, fee standards, risk warnings, account management and dispute resolution methods; 4. The platform mainly plays the role of a transaction matcher, asset custodian and information service provider, and does not assume investment responsibilities; 5. Be sure to read the user agreement carefully before using the platform to enhance yourself

Bitcoin halving affects the price of currency through four aspects: enhancing scarcity, pushing up production costs, stimulating market psychological expectations and changing supply and demand relationships; 1. Enhanced scarcity: halving reduces the supply of new currency and increases the value of scarcity; 2. Increased production costs: miners' income decreases, and higher coin prices need to maintain operation; 3. Market psychological expectations: Bull market expectations are formed before halving, attracting capital inflows; 4. Change in supply and demand relationship: When demand is stable or growing, supply and demand push up prices.

The latest price of Dogecoin can be queried in real time through a variety of mainstream APPs and platforms. It is recommended to use stable and fully functional APPs such as Binance, OKX, Huobi, etc., to support real-time price updates and transaction operations; mainstream platforms such as Binance, OKX, Huobi, Gate.io and Bitget also provide authoritative data portals, covering multiple transaction pairs and having professional analysis tools. It is recommended to obtain information through official and well-known platforms to ensure data accuracy and security.

PEPE coins are altcoins, which are non-mainstream cryptocurrencies. They are created based on existing blockchain technology and lack a deep technical foundation and a wide application ecosystem. 1. It relies on community driving forces to form a unique cultural label; 2. It has large price fluctuations and strong speculativeness, and is suitable for those with high risk preferences; 3. It lacks mature application scenarios and relies on market sentiment and social media. The prospects depend on community activity, team driving force and market recognition. Currently, it exists more as cultural symbols and speculative tools. Investment needs to be cautious and pay attention to risk control. It is recommended to rationally evaluate personal risk tolerance before operating.

CTEs are a feature introduced by MySQL8.0 to improve the readability and maintenance of complex queries. 1. CTE is a temporary result set, which is only valid in the current query, has a clear structure, and supports duplicate references; 2. Compared with subqueries, CTE is more readable, reusable and supports recursion; 3. Recursive CTE can process hierarchical data, such as organizational structure, which needs to include initial query and recursion parts; 4. Use suggestions include avoiding abuse, naming specifications, paying attention to performance and debugging methods.

The aggregation function is used to perform calculations on a set of values ??and return a single value. Common ones include COUNT, SUM, AVG, MAX, and MIN; GROUPBY groups data by one or more columns and applies an aggregation function to each group. For example, GROUPBYuser_id is required to count the total order amount of each user; SELECTuser_id, SUM(amount)FROMordersGROUPBYuser_id; non-aggregated fields must appear in GROUPBY; multiple fields can be used for multi-condition grouping; HAVING is used instead of WHERE after grouping; application scenarios such as counting the number of classified products, maximum ordering users, monthly sales trends, etc. Mastering these can effectively solve the number

MySQL's EXPLAIN is a tool used to analyze query execution plans. You can view the execution process by adding EXPLAIN before the SELECT query. 1. The main fields include id, select_type, table, type, key, Extra, etc.; 2. Efficient query needs to pay attention to type (such as const, eq_ref is the best), key (whether to use the appropriate index) and Extra (avoid Usingfilesort and Usingtemporary); 3. Common optimization suggestions: avoid using functions or blurring the leading wildcards for fields, ensure the consistent field types, reasonably set the connection field index, optimize sorting and grouping operations to improve performance and reduce capital

Choose safe and reliable Bitcoin transactions to be screened according to your own needs. The world's top platforms have their own characteristics. 1. Binance has the strongest comprehensive strength, sufficient liquidity and diverse services; 2. Ouyi derivatives have outstanding trading and stable technology; 3. Huobi has a deep history of precipitation and high security; 4. Gate.io has rich currency, suitable for potential projects; 5. Coinbase has strong compliance and is suitable for beginners; 6. Kraken has excellent security records, suitable for long-term holders; 7. KuCoin is active in the community and often launches small-cap potential coins; 8. Bybit contract trading experience is good, with an efficient interface; 9. Bitget provides order-following functions to lower trading thresholds; 10. Bitstamp has a long history of operation and institutions