Why should SELECT * be avoided in production queries?

< 1 min read

SELECT * should be avoided because it retrieves all columns, even if not required.
In one project, a dashboard query was slow because unnecessary columns were being loaded.
It increases data transfer between database and reporting layer.
It consumes more memory and impacts report performance.
If new columns are added to the table, SELECT * may unintentionally change output.
It also makes query logic less clear and harder to maintain.
Fetching only required columns improves performance and readability.
So in production, we always specify only the necessary fields.

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