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Michael Timbs
15,761 PointsPHP > Using PHP with MySQL > Limiting Records in SQL Queries > Using LIMIT with Descending Order
You are consistently using the following query in these videos
SELECT name, price, img, sku, paypal
Why not use the simple SELECT * query instead of manually typing every column in the table for each query? Is it in case the schema changes at a later date? Is this likely?
3 Answers
Juthawong Naisanguansee
Full Stack JavaScript Techdegree Graduate 80,724 PointsIn my experienced ,
When your database is very large like you stored a tons of information when you called all the table inside . It can lessen the performance.
and sometime it load the data that you didn't intend to use .
Such as loading blob which cause bloat in memory and slow down process.
There are some text you can learn more.
Sorry , I am new to this forum and I am quite bad at english
Michael Timbs
15,761 PointsI understand not using SELECT * for large tables but in the course videos there are only 5 columns in the table and he is manually selecting all the columns instead of just using SELECT *
Juthawong Naisanguansee
Full Stack JavaScript Techdegree Graduate 80,724 PointsYea. May be He should use Select * . It is a lot easier
Juthawong Naisanguansee
Full Stack JavaScript Techdegree Graduate 80,724 PointsSorry for misreading. I am too rush for the answer T^T
Michael Timbs
15,761 PointsNot a problem. Perhaps they are just trying to get people to use good practice in the event the table changes in the future or if someone watching the course is trying to work with larger tables.
Juthawong Naisanguansee
Full Stack JavaScript Techdegree Graduate 80,724 Points;) . Great man
Juthawong Naisanguansee
Full Stack JavaScript Techdegree Graduate 80,724 PointsHere is a couples of information :
http://stackoverflow.com/questions/3639861/why-is-select-considered-harmful
http://searchoracle.techtarget.com/answer/Why-select-star-is-bad