Why Should You Avoid `SELECT *` in SQL Queries?

*Why `SELECT ` is Generally a Bad Idea in SQL**

Using SELECT * might seem simple, but it's generally poor practice for several key reasons:

Performance Bottlenecks:

SELECT * fetches every column from a table, even if your application only needs a few. This leads to unnecessary data transfer between database and application, slowing things down and increasing the load on both.

Indexing Inefficiencies:

Including unneeded columns can interfere with database indexing. The database might have to use less efficient methods to retrieve data, resulting in slower queries.

Ambiguity and Errors:

Selecting all columns creates ambiguity if multiple tables in a query share column names. The application might misinterpret the data, leading to crashes or data corruption.

*When `SELECT ` Might Be Acceptable (Exceptions):**

Despite the downsides, there are limited situations where SELECT * can be useful:

Exploratory Data Analysis:

For quick checks or exploring unfamiliar tables, SELECT * offers a fast way to see all the data without needing to know specific column names beforehand.

Row Existence Checks:

In scenarios like counting rows or simply verifying if a row exists, SELECT * can be a concise way to represent "any row" rather than specifying a particular column.

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