Introduction to SQL for Data Engineering: write Basic queries.
Intro:
Hey guys here’s another article for you as you journey through your career as an aspiring Data Engineer . If you’ve been out on my other articles, do well to check them out in my profile. Like , comment, and share it to your friends as those article will be handful in your Data Engineering career.
SQL overview:
SQL (Structured Query Language) is a key in Data management,manipulation and organization . It is a fundamental skill in the field of data engineering.
Moreover, SQL is an essential tool for data engineering because it help to query databases . What this means is that SQL allows its user to interact with Data .
Why do we need to query Data after all?
Data Retrieval: With SQL, Data can be retrieved from a Data base efficiently . The SELECT statement helps to retrieve Data from a particular column.
Data Transformation: You can use SQL to clean and transform data before it is use for analytical process . SQL can allow you to delete , join or update Data in a particular column .
Data storage : Having and understanding of SQL is pertinent for managing Data repositories. SQL Data base can be use to store Data structured Data in Data pages.
SQL is also used to ensure compatibility and easy Data integration .
However, having had an overview of SQL and it’s importance I’m querying Data base, let’s look at some basic SQL commands.
Simple SQL commands:
1.SELECT:
The SELECT statement is the most vital SQL operation. It’s function is to retrieve Data from Data base table .
2.WHERE:
The WHERE query allows you to filter the rows returned by a SELECT statement based on a specific condition (link will be provided at the end of the article for practical tutorial)
3.JOIN
The JOIN operation allows for combination of Data from diverse table . For instance, joining column 1 from table A and Column 3 form table B . Some examples of JION are INNER JOIN, LEFT JOIN RIGHT JOIN AND FULL JOIN .
Some other examples of SQL commands include :
INSERT, UPDATE, DELETE CREATE etc
Conclusion:
The importance of having SWL skill cannot be over emphasized for Data Engineering. Mastering SWL is very crucial interacting with large Data base and for ETL task.
Happy learning!!!! And Enjoy your Data engineering journey.
SEE YOU SOON!!
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