Added extra question, addressed some formatting issues
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README.md
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README.md
@ -3,7 +3,7 @@
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:information_source: This repository contains interview questions on various DevOps related topics
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:information_source: This repository contains interview questions on various DevOps related topics
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:bar_chart: There are currently **300** questions
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:bar_chart: There are currently **312** questions
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:warning: You don't need to know how to answer all the questions in this repo. DevOps is not about knowing all :)
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:warning: You don't need to know how to answer all the questions in this repo. DevOps is not about knowing all :)
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@ -2017,6 +2017,7 @@ A short way of using if/else. An example:
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<summary>What does SQL stand for?</summary><br><b>
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<summary>What does SQL stand for?</summary><br><b>
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Structured Query Language
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Structured Query Language
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</b></details>
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</b></details>
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<details>
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<details>
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@ -2103,6 +2104,7 @@ Customer_ID | Customer_Name | Items_in_cart | Cash_spent_to_Date
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100206 | Bobby Frank | 1 | 100.20
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100206 | Bobby Frank | 1 | 100.20
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**ORDERS**
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**ORDERS**
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Customer_ID | Order_ID | Item | Price | Date_sold
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Customer_ID | Order_ID | Item | Price | Date_sold
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------------ | ------------- | ------------- | ------------- | -------------
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------------ | ------------- | ------------- | ------------- | -------------
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100206 | A123 | Rubber Ducky | 2.20 | 2019-09-18
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100206 | A123 | Rubber Ducky | 2.20 | 2019-09-18
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@ -2117,38 +2119,30 @@ Customer_ID | Order_ID | Item | Price | Date_sold
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<details>
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<details>
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<summary>How would I select all fields from this table?</summary><br><b>
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<summary>How would I select all fields from this table?</summary><br><b>
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Select *
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Select * <br>
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From Customers;
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From Customers;
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</b></details>
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</b></details>
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<details>
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<details>
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<summary>How many items are in John's cart?</summary><br><b>
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<summary>How many items are in John's cart?</summary><br><b>
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Select Items_in_cart
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Select Items_in_cart <br>
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From Customers
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From Customers <br>
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Where Customer_Name = "John Smith";
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Where Customer_Name = "John Smith";
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</b></details>
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</b></details>
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<details>
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<details>
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<summary>What is the sum of all the cash spent across all customers?</summary><br><b>
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<summary>What is the sum of all the cash spent across all customers?</summary><br><b>
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Select SUM(Cash_spent_to_Date) as SUM_CASH
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Select SUM(Cash_spent_to_Date) as SUM_CASH <br>
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From Customers;
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From Customers;
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</b></details>
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</b></details>
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<details>
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<details>
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<summary>How many people have items in their cart?</summary><br><b>
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<summary>How many people have items in their cart?</summary><br><b>
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Select count(1) as Number_of_People_w_items
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Select count(1) as Number_of_People_w_items <br>
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From Customers
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From Customers <br>
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where Items_in_cart > 0;
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</b></details>
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<details>
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<summary>How many people have items in their cart?</summary><br><b>
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Select count(1) as Number_of_People_w_items
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From Customers
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where Items_in_cart > 0;
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where Items_in_cart > 0;
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</b></details>
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</b></details>
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@ -2159,9 +2153,42 @@ You would join them on the unique key. In this case, the unique key is Customer_
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both the Customers table and Orders table
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both the Customers table and Orders table
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</b></details>
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</b></details>
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<details>
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<summary>How would you show which customer ordered which items?</summary><br><b>
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Select c.Customer_Name, o.Item <br>
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From Customers c <br>
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Left Join Orders o <br>
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On c.Customer_ID = o.Customer_ID;
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</b></details>
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<a name="sql-advanced"></a>
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<a name="sql-advanced"></a>
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#### Advanced
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#### Advanced
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<details>
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<summary>Using a with statement, how would you show who ordered cat food, and the total amount of money spent?</summary><br><b>
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with cat_food as ( <br>
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Select Customer_ID, SUM(Price) as TOTAL_PRICE <br>
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From Orders <br>
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Where Item like "%Cat Food%" <br>
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Group by Customer_ID <br>
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) <br>
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Select Customer_name, TOTAL_PRICE <br>
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From Customers c <br>
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Inner JOIN cat_food f <br>
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ON c.Customer_ID = f.Customer_ID <br>
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where c.Customer_ID in (Select Customer_ID from cat_food);
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Although this was a simple statement, the "with" clause really shines is when
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a complex query needs to be run on a table before joining to another. With statements are nice,
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because you create a pseudo temp when running your query, instead of creating a whole new table.
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The Sum of all the purchases of cat food weren't readily available, so we used a with statement to create
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the pseudo table to retrieve the sum of the prices spent by each customer, then join the table normally.
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</b></details>
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## Scenarios
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## Scenarios
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Scenarios are questions which don't have verbal answer and require you one of the following:
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Scenarios are questions which don't have verbal answer and require you one of the following:
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