Title: Database Queries
Last modified: August 21, 2016

---

# Database Queries

 *  [bbarton](https://wordpress.org/support/users/bbarton/)
 * (@bbarton)
 * [13 years ago](https://wordpress.org/support/topic/database-queries/)
 * Looking for opinions on which method is best.
 * Lets say I want to query all Posts based on user id, and along with that I need
   all Comments associated with each Post of the query. I see two solutions (could
   be more).
 * #1
    I take the result set of Posts query and loop through it, and for each Post
   I then query the Comments in database based on Post id.
 *     ```
       foreach($post as $key => $value){
       			$comments = query database here
       			$post[$key]->comments = $comments;
       		}
       ```
   
 * #2
    I query the Posts and query the Comments based on user id. Then loop through
   Posts and within that loop, loop through the Comments and compare the Comments
   Post id with the Post id.
 *     ```
       foreach($post as $key => $value){
       			foreach($comments as $k => $v){
       				if($v->comment_id == $value->id){
       					$post[$key]->comments = $comments[$k];
       				}
       			}
       }
       ```
   
 * I looking for the less expensive way for server load/bandwidth. More queries 
   vs 2 larger queries(All Posts & Comments -> User)?

Viewing 1 replies (of 1 total)

 *  Moderator [bcworkz](https://wordpress.org/support/users/bcworkz/)
 * (@bcworkz)
 * [13 years ago](https://wordpress.org/support/topic/database-queries/#post-3676045)
 * Interesting question. Either way returns the same amount of data, one with way
   more queries than the other. The first way, mySQL must search through a lot of
   data to return a small amount of data with each query.
 * The second way PHP must search through a lot of data to return a small amount
   of data for each iteration, though in this case the amount of data to search 
   through is smaller than mySQL’s data. Despite this, mySQL is probably more efficient
   because the DB is set up for this sort of searching. PHP stepping through arrays
   is quite crude in comparison.
 * But there’s a lot more queries made for mySQL to do the searching. While there’s
   a lot more exchanges, the actual increase in bandwidth is small because queries
   are very compact in comparison to the data returned.
 * I’ve no evidence to back this up, but I think letting mySQL do the searching 
   is more efficient, despite the increase in queries. It takes the load off PHP
   so the server can do other things it is better at while mySQL is doing it’s thing.
   IMHO of course.

Viewing 1 replies (of 1 total)

The topic ‘Database Queries’ is closed to new replies.

## Tags

 * [database](https://wordpress.org/support/topic-tag/database/)
 * [query](https://wordpress.org/support/topic-tag/query/)

 * In: [Hacks](https://wordpress.org/support/forum/plugins-and-hacks/hacks/)
 * 1 reply
 * 2 participants
 * Last reply from: [bcworkz](https://wordpress.org/support/users/bcworkz/)
 * Last activity: [13 years ago](https://wordpress.org/support/topic/database-queries/#post-3676045)
 * Status: not resolved

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