SQL for data analysis

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Introduction:

In the provided SQL query:

• The SELECT statement is used to indicate the columns you wish to retrieve in the result set.
• The FROM sales clause specifies the table from which the data is to be retrieved.
• AS followed by title is an alias that gives a name to the result column for clarity

How to find Minimum of a column in SQL for data analysis?

MIN() function applied to the “revenue” column, which will determine the minimum value in the “revenue” column.

minimum_revenue is the alias for the minimum value obtained using MIN().

Examples:

• This can be used to find out say city or state with minimum revenue from the given list,
• Suppose you have sales agents revenue data then you can find out what was the minimum revenue and to which sales agent it belongs to.

How to find Maximum of a column in SQL for data analysis?

MAX() function applied to the “revenue” column, which will find the maximum value in the “revenue” column.

Example:

• Suppose you have city or country wise revenue data then you can find out from which city or country you are earning maximum revenue
• Not only revenue it can be used on any numerical column for which you want to find the maximum value out of given set of values.

How to find Average of a column in SQL for data analysis?

AVG() function applied to the “revenue” column, which will calculate the average value of the “revenue” column.

Average is nothing but sum of all the values of the column divided by count of the values.

Examples:

• Suppose you have revenue of all the states of a country and want to know average revenue per state then this functions can be used,
• Another example can be of a class where you have data of all the students of a class and want to know

How to do divisions of two columns in SQL for data analysis?

In the below example by dividing two columns a third column named revenue_per_agent is created out of division of revenue w.r.t num_sales_agents.

Examples:

• This division function can be used anywhere i.e. in any place where you want to find some unit economics like in above case revenue_per_agent,
• Another example can be finding average revenue of a given set of sales of a particular product etc.

How to do addition of two or more columns in SQL for data analysis?

In the below example sum of two two columns i.e. sales_city1 and sales_city2 is stored in the final column known as combined_sales.

Note:

• The two columns that you are trying to add must be of numerical type otherwise it will start throwing error.

Conclusion:

SQL is a powerful language for data analysis, particularly for structured data in relational databases. It allows users to efficiently retrieve, aggregate, transform, and clean data, making it essential for generating statistics, data exploration, and decision-making. SQL’s performance and reproducibility, along with its ability to integrate with other tools and languages, make it a key component of data analysis workflows.

FAQs: