Amazon Development Centre India Data Analyst Interview Questions and Answers

I was asked a medium-level SQL question that involved the RANK function.

Q1. SQL related questions like joins
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Q2. Types of join in sql
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Types of join in SQL include inner join, left join, right join, and full outer join.
• Inner join returns only the matching records from both tables.

• Left join returns all records from the left table and the matching records from the right table.

• Right join returns all records from the right table and the matching records from the left table.

• Full outer join returns all records when there is a match in either the left or rig
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Q3. Practical use of left join
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A left join is used to combine data from two tables based on a common column, including all records from the left table.
• Left join returns all rows from the left table and the matching rows from the right table.

• It is useful when you want to retrieve all records from the left table, even if there are no matches in the right table.

• The result of a left join will have NULL values in the columns from the right table where th...read more
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Q4. Number of rows after applying certain join operations
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The number of rows after applying join operations depends on the type of join used and the data in the tables being joined.
• Inner join retains only the rows that have matching values in both tables

• Left join retains all rows from the left table and the matched rows from the right table

• Right join retains all rows from the right table and the matched rows from the left table

• Full outer join retains all rows when there is a
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Q5. Difference between vlookup in excel and some function in sql
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VLOOKUP in Excel is used to search for a value in a table and return a corresponding value, while SQL functions like JOIN and WHERE are used to retrieve data from multiple tables based on specified conditions.
• VLOOKUP is specific to Excel and works on a single table, while SQL functions can work on multiple tables.

• VLOOKUP requires the table to be sorted in ascending order, while SQL functions do not have this requiremen...read more
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