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Why is SELECT * bad practice? Wouldn't it mean less code to change if you added a new column you wanted?

I understand that SELECT COUNT(*) is a performance problem on some DBs, but what if you really wanted every column?

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SELECT * is bad practice because it is most expensive to query data when you need only a couple of columns. If you want to retrieve only a few columns of that table then using SELECT * is just the additional and unnecessary work for the database server. Using SELECT *  when needed only specific columns lead to unnecessary information that has to be passed over the database server. This consumes more processing time when you have huge data.

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