Introduction to SQL: Glossary

SQL is a powerful language used to interrogate and manipulate relational databases.

SQL is ideal for querying databases

SQL queries have a basic query structure starting with SELECT field FROM table with additional keywords and criteria that can be used.

Use WHERE to filter and retrieve data based on specific conditions.

Use AND, OR, and NOT to add additional conditions.

Use the comparison keyword LIKE and wildcard characters such as % to match patterns.

Queries can do arithmetic operations on field values.

Joining two tables in SQL is an good way to analyse datasets, especially when both datasets provide partial answers to questions you want to ask.

Creating aliases allows us to spend less time typing, and more time querying!

Saving queries as ‘Views’ allows you to save time and avoid repeating the same operation more than once.

Database design is helpful for creating more efficient databases.

Use CREATE and DROP to create and delete tables.

Use INSERT to add data.

Use UPDATE to modify existing data.

Use DELETE to remove data.

It is simpler and safer to modify data when every record has a unique primary key.

Do not create dangling references by deleting records that other records refer to.

There are additional database tools beyond DB Browser and SqliteOnline.

It takes time and practice to learn how to translate plain English queries into SQL queries.

There are many ways to write an SQL queries, but some look better than others.