Вводный курс: содержит основы SQL и будет полезен начинающим изучение.
▫️Урок 1. Что такое SQL? Установка локального сервера.
▫️Урок 2. Создание БД, таблиц и работа с ними.
▫️Урок 3. Добавление и обновление записей в БД.
▫️Урок 4. Удаление данных из БД.
▫️Урок 5. Выборка данных из БД. Where, Order, Limit.
▫️Урок 6. Создание индексов и работа с ними.
▫️Урок 7. Объединение данных.
▫️Урок 8. Псевдонимы, функции и Group By
BY SQL для тестировщика
Most people buy Bitcoin via exchanges, such as Coinbase. Exchanges allow you to buy, sell and hold cryptocurrency, and setting up an account is similar to opening a brokerage account—you’ll need to verify your identity and provide some kind of funding source, such as a bank account or debit card. Major exchanges include Coinbase, Kraken, and Gemini. You can also buy Bitcoin at a broker like Robinhood. Regardless of where you buy your Bitcoin, you’ll need a digital wallet in which to store it. This might be what’s called a hot wallet or a cold wallet. A hot wallet (also called an online wallet) is stored by an exchange or a provider in the cloud. Providers of online wallets include Exodus, Electrum and Mycelium. A cold wallet (or mobile wallet) is an offline device used to store Bitcoin and is not connected to the Internet. Some mobile wallet options include Trezor and Ledger.
In general, many financial experts support their clients’ desire to buy cryptocurrency, but they don’t recommend it unless clients express interest. “The biggest concern for us is if someone wants to invest in crypto and the investment they choose doesn’t do well, and then all of a sudden they can’t send their kids to college,” says Ian Harvey, a certified financial planner (CFP) in New York City. “Then it wasn’t worth the risk.” The speculative nature of cryptocurrency leads some planners to recommend it for clients’ “side” investments. “Some call it a Vegas account,” says Scott Hammel, a CFP in Dallas. “Let’s keep this away from our real long-term perspective, make sure it doesn’t become too large a portion of your portfolio.” In a very real sense, Bitcoin is like a single stock, and advisors wouldn’t recommend putting a sizable part of your portfolio into any one company. At most, planners suggest putting no more than 1% to 10% into Bitcoin if you’re passionate about it. “If it was one stock, you would never allocate any significant portion of your portfolio to it,” Hammel says.
SQL для тестировщика from ar