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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

Why MySQL You Need to Master for Data Analytics Jobs

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MySQL Before you can start analysing data, you are going to actually have to have some data on hand. That means a database – preferably a relational one. If you had your sights set on a non-relational, NoSQL database solution, you might want to step back and catch your breath. NoSQL databases are unique because of their independence from the Structured Query Language (SQL) found in relational databases. Relational databases all use SQL as the domain-specific language for ad hoc queries, whereas non-relational databases have no such standard query language, so they can use whatever they want –including SQL. Non-relational databases also have their own APIs designed for maximum scalability and flexibility. When You Need to Learn NoSQL Databases? NoSQL databases are typically designed to excel in two specific areas: speed and scalability. But for the purposes of learning about data concepts and analysis, such super-powerful tools are pretty much overkill. In other words, you