SQL optimized IO calls (comparing mutiple IOs or single IO with huge data)

Question

I have a SQL table Student. It has 30 columns (properties) for each student.

I need 10 properties in a SQL query.

Which one is better approach ?

for k in properties:

 `q1 = 'SELECT k FROM STUDENTS where uid in %s'%tuple(list1);`

Mainly comparison is between single I/O with huge amount of data or multiple I/O with less amount of data

I think the 1st approach is better as in single IO all data will be loaded to memory then iterating over it is faster in memory

If you only need 10 out of 30 fields, why does option 1 select all 30? — Dan Bracuk, Nov 05 '15 at 17:31
This is one of those cases where the most accurate response will be whatever you determine from trying it yourself, in your own environment, under your conditions. — Andy Lester, Nov 05 '15 at 18:40

score 0 · Answer 1 · answered Nov 05 '15 at 17:32

0

select k1, k2, k3, k4, k5, k6, k7, k8, k9, k10 from STUDENTS where uid in %s'%tuple(list1);

answered Nov 05 '15 at 17:32

paparazzo

That i know. But due to some reasons i wanted to compare option mentioned in question. Let suppose I have constraint , due to which i cant use your approach – Prannoy Mittal Nov 05 '15 at 19:21
Really you can do a * but not that due to a constaint – paparazzo Nov 05 '15 at 22:58

1 Answers1