XF 2.2 How to do a select?

[Robert9]

Some thoughts from a beginner about a mysql-query.

Lets say i need some new fields for xf_user.

Which colors do you like?
red, green, blue, yellow, grey, orange

1. I could add now some fields like:

xf_user.red
xf_user.green
xf_user.blue
xf_user.yellow

(or color1, color2, color3)

select * from xf_user where red = 1 AND green=1

but we dont like to have so many new fields here.


2. I could add a textfield

xf_user.colors with value "greenbludyellow"

select * from xf_user where colors like %green% and colors like %yellow%

because this will not fit, we need to save

xf_user.colors with value "xgreenbludyellowx" (else green will not be found with %green%! Also %yellow% will not be found!)



3. Also i could have a list like
red = 1
green = 2
blue = 3
yellow = 4

xf_user.colors with value ".23."
select * from xf_user where colors like %2% OR colors like %3%



4. Should i think about to save bits for the search with "AND"?
red = 1
green = 2
blue = 4
yellow = 8


red, yellow => 1+8 = 9

to search for red and yellow
select * from xf_user where colors = 9
what is better than
select * from xf_user where colors like %1% AND colors like %8%

for the search with AND this makes sense to me, but what is with a search with OR?

to find red or yellow we have to query for

select * from xf_user where colors = 1 OR colors = 8 OR colors = 9
but with as an example eight values/bits we have a lot of "OR" and many combinations (255), then it is maybe better just to query:
select * from xf_user where colors like %1% OR colors like %2% OR ... colors like %9%



Is there anything else much better to use for a query with AND and/or OR?

bits for select-field
text with like %x% for radio-field?

 

[Robert9]

For AND i guess, it is clear just to save an integer and index it.
For OR the best idea seoms to me now to allow only three choices for example.
Then i have a max of eight integers and do an select with IN().
Also it is maybe a good idea to use the opposite of a search.

If i choose five checkboxes from eight, i can search for
where not in [the other three checkboxes]! then i have to search always for a max of 2^4! right?


Another strategy could be fields for fields?

Sports 0/1, is set if fields soccer, badmington, volleyball has set at least one. So we dont look for them, we search only sports 0/1, means we have an OR for them. Not funny, if i search for soccer and get the other two.

hmmm ...

 

[Lukas W.]

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[Robert9]

But then there is not index, right?
I will check later how the filter-addons do the job.
But probably i will use bits and reduce the search to 3 or 4 checkboxes, if possible.

 

[Lukas W.]

If you're reliant on efficient querying, store it in a relational table with respective indices, see xf_thread_watch as an example. If it's only for the occasional query, find_in_set() will perform fine, especially on smaller tables.

 

[Robert9]

Here is a real example, and while it the usertable, i will be more than some 10.000s,
at least if i dont use a time limit for last_online.

1. user.age (> x, < y)
2. user.haircolor (radio), one of x as interger
3. user.hobbies (select) x of y

1 and 2 are ok and indexed.

But what to do with 3?

For search with "and" i will use bits.
But what can i do with search with "OR"?
I have 16 different values with 0/1.


But maybe i make myself to much headaches.
I can try to reduce to 10 values and save them
two times.

As an indexed bit_value for the search with AND
and as an integer like
9876543210 with where x LIKE y? But this will be not indexed.

Sorry, to think loud here. I cant find any text with infos about this.
Probably i have the wrong phrases to search for. This problem should be solved a billion times before.