[英]SQL SELECT and PHP retrive speed INT vs TINYINT vs VARCHAR vs ENUM?
[英]SQL SELECT and PHP retrive speed using single table VS join two table?
我正在創建一個表,然后顯示記錄。 我想以“ 英寸 ”格式顯示用戶身高,但它將以“ cm ”格式存儲在用戶表中。 現在我想知道哪種方法可以使我更快地得到結果?
使用JOIN
// to select records
SELECT *.u FROM, h.height_inch user as u join height as h on u.height_cm =h.height_cm
WHERE u.user_id = 2 AND ...;
//for display in php
foreach($all_records AS $key => $val) {
echo $val['height_inch'];
}
或單用戶表(更快/低於):
// to select records
SELECT * user WHERE u.user_id = 2 AND ...;
//for display in php
foreach($all_records AS $key => $val) {
$height_in_cm = $val['height_inch']
$height_in_inch= convert_to_inch($height_in_cm); //function for convert height cm to inch..
echo $height_in_inch;
}
甚至更快的替代方法是僅在SQL中執行算術運算,因此您不必存儲固定的轉換數據或遍歷結果。
SELECT height_cm, height_inches as (height_cm / 2.54) FROM table;
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