Essential SQL Queries and Tips for Aspiring Analysts.

SQL is a powerful language for querying and manipulating data in databases. It is used by data analysts, data scientists, and other professionals who need to extract insights from data.

Many different techniques and queries can be used in SQL. Here are 10 of the most important ones:

Retrieve data. The SELECT clause in the query specifies the columns that we want to return.
```
 SELECT *
 FROM orders
```
Counting rows and items. The COUNT() function can be used to count the number of rows or items in a table.
```
 SELECT COUNT(*) AS total_rows
 FROM orders;
```
Aggregation functions. Aggregation functions, such as SUM(), AVG(), and MAX(), can be used to calculate summary statistics on a group of data.
```
 SELECT product_id, SUM(price) AS total_sales, AVG(price)
 FROM orders
```
Extreme value identification. The MIN() and MAX() functions can be used to identify the minimum and maximum values in a dataset.
```
 SELECT MIN(price) AS minimum_price, MAX(price) AS maximum_price
 FROM orders;
```

Slicing data. The WHERE clause can be used to filter data based on specific criteria.

 SELECT *
 FROM orders
 WHERE date > CURRENT_DATE - INTERVAL 30 DAY;

 /* This code will return all rows from the orders table where 
 the date column is greater than the current date minus 30 days.*/

Limiting data. A LIMIT clause can be used to restrict the number of rows that are returned by a query.
```
 SELECT *
 FROM orders
 LIMIT 10;
```

Sorting data. The ORDER BY clause can be used to sort data in ascending or descending order.

 SELECT *
 FROM orders
 ORDER BY price, date;

 /*This code will return all rows from the orders table, sorted by 
 the price column in ascending order, and then by the date 
 column in ascending order. */

Filtering patterns. The LIKE clause can be used to filter data based on a pattern.

 SELECT *
 FROM orders
 WHERE product_name LIKE '%phone%';

 /* This code will return all rows from the orders table where 
 the product_name column contains the word "phone"*/

Grouping data. The GROUP BY clause can be used to group data together and calculate summary statistics on each group.

 SELECT product_name, SUM(price) AS total_sales
 FROM orders
 GROUP BY product_name;

 /*This code will group the orders table by product_name and total
 sales for each product. The GROUP BY clause specifies the column 
 that the data is grouped by. In this case, the GROUP BY clause 
 specifies that the data is grouped by the product_name column.*/

Combining data. The JOIN clause in SQL is used to combine data from two or more tables. This is a powerful way to query data, as it allows you to combine data that is related in different tables.
```
SELECT orders.order_id, orders.product_name, customers.customer_name
FROM orders
JOIN customers ON orders.customer_id = customers.customer_id;

/* This code will combine data from the orders table and 
the customers table. The JOIN clause specifies that the orders 
table and the customers table are joined on the customer_id column.*/
```
These are just a few of the many techniques and queries that can be used in SQL. By mastering these techniques, you will be able to query and manipulate data with ease.

If you are new to SQL, I encourage you to start learning today. There are many resources available online, such as tutorials, courses, and books. With a little effort, you can quickly become proficient in SQL and start using it to analyze data.

Here are some additional tips for learning SQL:

Start with the basics. Learn about the different types of SQL queries and how to use them.
Practice regularly. The more you practice, the better you will become at writing SQL queries.
Use a good IDE. A good IDE will help you write and debug SQL queries more easily.
Join a community. There are many online communities where you can ask questions and get help from other SQL users.

I hope this article has been helpful. If you have any questions, please feel free to ask in the comments below.