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SQL Interview Success: Unlocking the Top 5 Frequently Asked Queries

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 Here are the five top commonly asked SQL queries in the interviews. These you can expect in Data Analyst, or, Data Engineer interviews. Top SQL Queries for Interviews 01. Joins The commonly asked question pertains to providing two tables, determining the number of rows that will return on various join types, and the resultant. Table1 -------- id ---- 1 1 2 3 Table2 -------- id ---- 1 3 1 NULL Output ------- Inner join --------------- 5 rows will return The result will be: =============== 1  1 1   1 1   1 1    1 3    3 02. Substring and Concat Here, we need to write an SQL query to make the upper case of the first letter and the small case of the remaining letter. Table1 ------ ename ===== raJu venKat kRIshna Solution: ========== SELECT CONCAT(UPPER(SUBSTRING(name, 1, 1)), LOWER(SUBSTRING(name, 2))) AS capitalized_name FROM Table1; 03. Case statement SQL Query ========= SELECT Code1, Code2,      CASE         WHEN Code1 = 'A' AND Code2 = 'AA' THEN "A" | "A

The Essential Guide to Blockchain Terminology

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Bitcoin was the first project developed by using blockchain. My post is to share Blockchain keywords by using an example of Bitcoin. Let us ready... Blockchain is new technology. Understanding its principles makes you helpful to apply in your projects.  Initially, the purpose of  Blockchain development was to carry mining. In general, mining means search and find value. Usually, mining processes are two types. Those are data mining and bitcoin mining . Blockchain Glossary Blockchain - only blocks involved. The data which was finalized stored in blocks. Bitcoin Ledger - It is a public ledger Ledger or Blockchain - The chain of blocks Functions of Blockchain - It validates each transaction, Keeps track, and verifies ownership Double Spending- It prevents duplicating the Cryptocurrency for using next time. Consensus mechanism - It is also called PoW (proof of work). This mechanism avoids double-spending Group of Transactions - When a new group of transactions created, t

4 Must read Blockchain Disadvantages for Consumers

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Here are the disadvantages of Blockchain. Below, you will find the list of these. Blockchain Disadvantages Lack of privacy Loss of personal responsibility Loss of jobs Reintermediation 1. Lack of Privacy Public blockchains do not hide any of their data. Instead, everyone can read the complete history of transactions. This level of transparency is frightening for those who want to protect their privacy. These concerns are understandable when considering the level at which personal data are already collected and utilized by large corporations or intelligence agencies. 2. Loss of Responsibility Loss of personal responsibility is often considered a consequence of disintermediation. Intermediaries not only bring different parties of a contract together but may also provide guarantees. They offer reconciliation in cases when transactions do not work out as intended, and they are also obliged to take responsibility for their actions. The shift from trust in people and human organizations to