21/06/2024
What is the best way to learn SQL?
In 1986, SQL (Structured Query Language) became a standard. Over the next 40 years, it became the dominant language for relational database management systems. Reading the latest standard (ANSI SQL 2016) can be time-consuming. How can I learn it?
There are 5 components of the SQL language:
- DDL: data definition language, such as CREATE, ALTER, DROP
- DQL: data query language, such as SELECT
- DML: data manipulation language, such as INSERT, UPDATE, DELETE
- DCL: data control language, such as GRANT, REVOKE
- TCL: transaction control language, such as COMMIT, ROLLBACK
For a backend engineer, you may need to know most of it. As a data analyst, you may need to have a good understanding of DQL. Select the topics that are most relevant to you.
Over to you: What does this SQL statement do in PostgreSQL: βselect payload->ids->0 from eventsβ?