Basic Query Syntax

Let’s work on some exercises and see how each query works. Each exercise gives an overview and examples before we start applying what we learn in each section.

An example of the “Products” table is given below, which we’ll be using in the next few exercises.

The query structure

Understanding the syntax and its structure is extremely helpful for the future. Let’s delve into the basics of one of the most common statements, the SELECT statement, which we use to retrieve data.

In the query above, we select two columns and all rows from the table.

Since we’re selecting two columns, the query would perform much faster than if we were to select all of the columns like this:

The WHERE clause

We use the WHERE clause to filter the number of rows a query can return. This clause uses a condition, such as if a column is equal to, greater than, less than, between, or like a certain value.

When writing the syntax, it’s important to remember that the WHERE condition comes after the FROM statement. The types of operators vary based on the type of data that we’re filtering.

The EQUALS operator

We use the EQUALS operator when finding an exact match. The syntax below uses the WHERE clause for a column that contains the exact string of 'Value'.

Note: The strings need single quotes around them. However, numeric values do not.

The BETWEEN operator

Typically, we use the BETWEEN operator for finding values between a certain range of numbers or date ranges. It’s important to note that the first value in the BETWEEN comparison operator should be lower than the value on the right—for example, comparison between 10 ...