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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

Understand Data power why quality everyone wants

Information and data quality is new service work for data intense companies. I have seen not only in Analytics projects but in Mainframe projects, there is the Data Quality team. How incorrect data impact on us Information quality problems and their impact are all around us: A customer does not receive an order because of incorrect shipping information. Products are sold below cost because of wrong discount rates. A manufacturing line is stopped because parts were not ordered—the result of inaccurate inventory information. A well-known U.S. senator is stopped at an airport (twice) because his name is on a government "Do not fly" list. Many communities cannot run an election with results that people trust. Financial reform has created new legislation such as Sarbanes—Oxley.  Incorrect data leads to many problems. The role of Data Science is to use quality data for effective decisions. What is information Information is not simply data, strings of numbers, lis