I'm implementing search functionality into my application, and I need to write the SQL query that will search the database for records based on a wide range of possible parameters. I'm including a sample of what I have so far:
SELECT m.*, a.*, p.*, e.*
FROM members m
LEFT JOIN addresses a ON m.member_id = a.address_member_id AND a.preferred_address = TRUE
LEFT JOIN phones p ON m.member_id = p.phone_member_id AND p.preferred_phone = TRUE
LEFT JOIN emails e ON m.member_id = e.email_member_id AND e.preferred_email = TRUE
WHERE m.member_id IN (
(SELECT address_member_id
FROM addresses
WHERE address = '123 Hart Ct' AND unit = NULL AND city = 'Hometown' AND state = 'NJ' AND zip_code = '08895'),
(SELECT phone_member_id
FROM phones
WHERE area_code = '732' AND prefix = '619' AND line_number = '7826'),
(SELECT email_member_id
FROM emails
WHERE email_address = 'craigmiller160#gmail.com')
)
AND m.first_name = 'Jane' AND m.middle_name = 'Deborah' AND m.last_name = 'Foster'
ORDER BY member_id ASC;
As you can see, I'm searching for records in the "members" table based on the values in that table, as well as the values of the "preferred" address, phone, email, etc, that are associated with it.
The problem is that the query above requires all of those values to be provided. In most cases, the user will only provide a handful of the actual values to perform the search.
Now, I know that one option is to build the query dynamically in my application layer, concatenating Strings together and whatnot. That way the WHERE clauses would only have the values that are needed for that specific query. But before I do that, I'm wondering if there's any way to accomplish this in a purely-SQL way?
You have two options to do this in purely-SQL way
The first way is using a stored procedure. Using it you can use IF condition and concatenate the query string inside the stored procedure and then execute it (I can provide a demo if you want)
The second way is using an OR condition
SELECT m.*, a.*, p.*, e.*
FROM members m
LEFT JOIN addresses a ON m.member_id = a.address_member_id
AND a.preferred_address = TRUE
LEFT JOIN phones p ON m.member_id = p.phone_member_id
AND p.preferred_phone = TRUE
LEFT JOIN emails e ON m.member_id = e.email_member_id
AND e.preferred_email = TRUE
WHERE m.member_id IN ((SELECT address_member_id
FROM addresses
WHERE ('123 Hart Ct' is NULL OR address = '123 Hart Ct')
AND (NULL is NULL OR unit = NULL)
AND ('Hometown' is NULL OR city = 'Hometown')
AND ('NJ' is NULL OR state = 'NJ')
AND ('08895' IS NULL OR zip_code = '08895'));
Note you can replace is NULL with = "" if the variable will be empty not NULL
Related
I'm not good with sql so i need help exporting my customer's first names, email address, their country and if possible last times they had access to the store.
I managed to get email and first name by using this query :
SELECT firstname, lastname, email, active FROM psdb_customer
From what i understood, since the other data is stored in a different db table, i should use a join to get data from both tables but i haven't been able to figure out how
Any help is welcome
In the past, I helped someone with something similar in the PrestaShop forum. This query should work, just remember that to get a country of a customer they should have at least one address registered and of course I'm using the default db prefix:
SELECT a.`firstname`,
a.`lastname`,
a.`email`,
(SELECT c.`date_add`
FROM `ps_guest` g
LEFT JOIN `ps_connections` c ON c.`id_guest` = g.`id_guest`
WHERE g.`id_customer` = a.`id_customer`
ORDER BY c.`date_add` DESC LIMIT 1) AS `last_activity`,
(SELECT cl.`name`
FROM `ps_address` ad
LEFT JOIN `ps_country_lang` cl ON cl.`id_country` = ad.`id_country`
WHERE ad.`id_customer` = a.`id_customer`
ORDER BY ad.`id_address` DESC LIMIT 1) AS `country_name`
FROM `ps_customer` a
Rolige's answer is what i was looking for.
Here is another query that allows filtering the results by country (using the id_country)
SELECT SQL_CALC_FOUND_ROWS a.`id_address`,
a.firstname as firstname,
a.lastname as lastname,
cl.id_country as country, cl.`name` as country
FROM `ps_address` a
LEFT JOIN `ps_country_lang` cl ON (cl.`id_country` = a.`id_country`
AND cl.`id_lang` = 1)
LEFT JOIN `ps_customer` c ON a.id_customer = c.id_customer
WHERE 1 AND a.id_customer != 0
AND c.id_shop IN (1)
AND a.`deleted` = 0
AND cl.`id_country` = '8'
ORDER BY a.`id_address` ASC
I have query like this:
SELECT cs_event.*, cs_file.name, cs_file.extension, cs_user.first_name, cs_user.last_name
FROM cs_event
LEFT JOIN cs_file ON cs_event.idfile = cs_file.idfile
LEFT JOIN cs_user ON cs_event.iduser = cs_user.iduser
WHERE type != 51
AND idportal = 1
UNION DISTINCT
SELECT cs_event.*, cs_file.name, cs_file.extension, cs_user.first_name, cs_user.last_name
FROM cs_event
LEFT JOIN cs_file ON cs_event.idfile = cs_file.idfile
LEFT JOIN cs_user ON cs_event.iduser = cs_user.iduser
WHERE shared_with_users LIKE '%i:2;%'
AND idportal = 1
ORDER BY add_date DESC
LIMIT 6
The problem is following:
Regular user can't see certain types of events (for now it is type 51) and he can see only things which are shared with him.
shared_with_users column can be null or have value - this column have value only for one type of event (type = 50) and for other events it is null.
I need to perform following:
User can access all events except event with type 51 and if the the event is type of 50, I need to check if the event is shared with him (shared_with_users column), and collect that also. Is it possible to make this kind of query?
Try this
SELECT cs_event.*, cs_file.name, cs_file.extension, cs_user.first_name, cs_user.last_name
FROM cs_event
LEFT JOIN cs_file ON cs_event.idfile = cs_file.idfile
LEFT JOIN cs_user ON cs_event.iduser = cs_user.iduser
WHERE type != 51 o or (type = 50 and shared_with_users LIKE '%i:2;%')
AND idportal = 1
ORDER BY add_date DESC
LIMIT 6
I think you can do this as a single query, with logic in the WHERE clause:
SELECT e.*, f.name, f.extension, u.first_name, u.last_name
FROM cs_event e LEFT JOIN
cs_file f
ON e.idfile = f.idfile LEFT JOIN
cs_user u
ON e.iduser = u.iduser
WHERE idportal = 1 AND
(type <> 51 OR shared_with_users LIKE '%i:2;%');
Some notes:
I don't think the LEFT JOINs are necessary. The WHERE clause may be turning them into inner joins anyway, but it is hard to tell without qualified column names.
I added table aliases so the query is easier to write and to read.
The logic for shared_with_users suggests that you have stored a list of values in a string. That is a bad choice.
I have a table with news items, I have another table with media_types, I want to make one simple query that reads the media_types table and count for each record how many news_items exist.
The result will be turned into a json response that I will use for a chart, this is my SQLstatement
SELECT
gc.country AS "country"
, COUNT(*) AS "online"
FROM default_news_items AS ni
JOIN default_news_item_country AS nic ON (nic.id = ni.country)
JOIN default_country AS c ON (nic.country = c.id)
JOIN default_geo_country AS gc ON (gc.id = c.geo_country)
LEFT JOIN default_medias ON (m.id = ni.media)
WHERE TRUE
AND ni.deleted = 0
AND ni.date_item > '2013-10-23'
AND ni.date_item < '2013-10-29'
AND gc.country <> 'unknown'
AND m.media_type = '14'
GROUP BY gc.country
ORDER BY `online` desc LIMIT 10
This is the json respond I create from the mysql respond
[
{"country":"New Zealand","online":"7"},
{"country":"Switzerland","online":"1"}
]
How do I add print and social data to my output like this
I would like the json respond look like this
[
{"country":"New Zealand","online":"7", "social":"17", "print":"2"},
{"country":"Switzerland","online":"1", "social":"7", "print":"1"}
]
Can I use the count (*) in the select statement to do something like this
COUNT( * ) as online, COUNT( * ) as social, COUNT( * ) as print
Is it possible or do I have to do several SQL statement to get the data I'm looking for?
This is the general structure:
SELECT default_geo_country.country as country,
SUM(default_medias.media_type = 14) as online,
SUM(default_medias.media_type = XX) as social,
SUM(default_medias.media_type = YY) as print
FROM ...
JOIN ...
WHERE ...
GROUP BY country
I think you want conditional aggregation. Your question, however, only shows the online media type.
Your query would be more readable by using table aliases and removing the back quotes. Also, if media_type is an integer, then you should not enclose the constant for comparison in single quotes -- I, for one, find it misleading to compare a string constant to an integer column.
I suspect this is the way you want to go. Where the . . . is, you want to fill in with the counts for the other media types.
SELECT default_geo_country.country as country,
sum(media_type = '14') as online,
sum(default_medias.media_type = XX) as social,
sum(default_medias.media_type = YY) as print
. . .
FROM default_news_items ni JOIN
default_news_item_country nic
ON nic.id = ni.country JOIN
default_country dc
ON nic.country = dc.id JOIN
default_geo_country gc
ON gc.id = dc.geo_country LEFT JOIN
default_medias dm
ON dm.id = dni.media
WHERE ni.deleted = '0'
AND ni.date_item > '2013-10-23'
AND ni.date_item < '2013-10-29'
AND gc.country <> 'unknown'
GROUP BY gc.country
ORDER BY online desc
LIMIT 10
Basically I have three MySQL tables:
Users - contains base information on users
Fields - describes additional fields for said users (e.g. location, dob etc.)
Data - Contains user data described via links to the fields table
With the basic design as follows (the below is a stripped down version)
Users:
ID | username | password | email | registered_date
Fields
ID | name | type
Data:
ID | User_ID | Field_ID | value
what I want to do is search Users by the values for the fields they have, e.g. example fields might be:
Full Name
Town/City
Postcode
etc.
I've got the following, which works when you're only wanting to search by one field:
SELECT `users`.`ID`,
`users`.`username`,
`users`.`email`,
`data`.`value`,
`fields`.`name`
FROM `users`,
`fields`,
`data`
WHERE `data`.`Field_ID` = '2'
AND `data`.`value` LIKE 'london'
AND `users`.`ID` = `data`.`User_ID`
AND `data`.`Field_ID` = `fields`.`ID`
GROUP BY `users`.`ID`
But what about if you want to search for Multiple fields? e.g. say I want to search for Full Name "Joe Bloggs" With Town/City set to "London"? This is the real sticking point for me.
Is something like this possible with MySQL?
I'm going with the assumption that "searching multiple fields" is talking about the Entity-Attribute-Value structure.
In that case, I propose that the first step is to create a derived query - basically, we want to limit the "EAV data joined" to only include the records that have the values we are interested in finding. (I've altered some column names, but the same premise holds.)
SELECT d.userId
FROM data d
JOIN fields f
ON f.fieldId = d.fieldId
-- now that we establish data/field relation, filter rows
WHERE f.type = "location" AND d.value = "london"
OR f.type = "job" AND d.value = "programmer"
This resulting rows are derived from the filtered EAV triplets that match our conditions. Only the userId is selected in this case (as it will be used to join against the user relation), but it is also possible to push fieldId/value/etc through.
Then we can use all of this as a derived query:
SELECT *
FROM users u
JOIN (
-- look, just goes in here :)
SELECT DISTINCT d.userId
FROM data d
JOIN fields f
ON f.fieldId = d.fieldId
WHERE f.type = "location" AND d.value = "london"
OR f.type = "job" AND d.value = "programmer"
) AS e
ON e.userId = u.userId
Notes:
The query planner will figure all the RA stuff out peachy keen; don't worry about this "nesting" as there is no dependent subquery.
I avoid the use of implicit cross-joins as I feel they muddle most queries, this case being a particularly good example.
I've "cheated" and added a DISTINCT to the derived query. This will ensure that at most one record will be joined/returned per user and avoids the use of GROUP BY.
While the above gets "OR" semantics well (it's both easier and I may have misread the question), modifications are required to get "AND" semantics. Here are some ways that the derived query can be written to get such. (And at this point I must apologize to Tony - I forget that I've already done all the plumbing to generate such queries trivially in my environment.)
Count the number of matches to ensure that all rows match. This will only work if each entity is unique per user. It also eliminates the need for DISTINCT to maintain correct multiplicity.
SELECT d.userId
FROM data d
JOIN fields f
ON f.fieldId = d.fieldId
-- now that we establish data/field relation, filter rows
WHERE f.type = "location" AND d.value = "london"
OR f.type = "job" AND d.value = "programmer"
GROUP BY d.userId
HAVING COUNT(*) = 2
Find the intersecting matches:
SELECT d.userId
FROM data d
JOIN fields f ON f.fieldId = d.fieldId
WHERE f.type = "location" AND d.value = "london"
INTERSECT
SELECT d.userId
FROM data d
JOIN fields f ON f.fieldId = d.fieldId
WHERE f.type = "job" AND d.value = "programmer"
Using JOINS (see Tony's answer).
SELECT d1.userId
FROM data d1
JOIN data d2 ON d2.userId = d1.userId
JOIN fields f1 ON f1.fieldId = d1.fieldId
JOIN fields f2 ON f2.fieldId = d2.fieldId
-- requires AND here across row
WHERE f1.type = "location" AND d1.value = "london"
AND f2.type = "job" AND d2.value = "programmer"
An inner JOIN itself provides conjunction semantics when applied outside of the condition. In this case I show "re-normalize" the data. This can also be written such that [sub-]selects appear in the select clause.
SELECT userId
FROM (
-- renormalize, many SO questions on this
SELECT q1.userId, q1.value as location, q2.value as job
FROM (SELECT d.userId, d.value
FROM data d
JOIN fields f ON f.fieldId = d.fieldId
WHERE f.type = "location") AS q1
JOIN (SELECT d.userId, d.value
FROM data d
JOIN fields f ON f.fieldId = d.fieldId
WHERE f.type = "job") AS q2
ON q1.userId = q2.userId
) AS q
WHERE location = "london"
AND job = "programmer"
The above duplicity is relatively easy to generate via code and some databases (such as SQL Server) support CTEs which make writing such much simpler. YMMV.
If I understood you right, this is what you want:
FROM `users`,
`fields`,
`data` `location`
`data` `name`
WHERE `location`.`Field_ID` = '2'
AND `location`.`value` LIKE 'london'
AND `location`.`Field_ID` = `fields`.`ID`
AND `name`.`Field_ID` = 'whathere? something for its name'
AND `name`.`value` LIKE 'london'
AND `name`.`Field_ID` = `fields`.`ID`
AND `users`.`ID` = `data`.`User_ID`
I'd prefer joins though
Well here you hit one of the downsides of the EAV you are using
SELECT u.ID, u.username,u.email, d1.value, f1.Name, d2.Value, f2.name
FROM `users` u,
inner join data d1 On d1.User_id = u.id
inner join data d2 On d2.User_id = u.id
inner join fields f1 on f1.id = d1.field_id
inner join fields f2 on f2.id = d2.field_id
WHERE d1.Field_id = '2' and d1.Value = 'london'
and d2.field_id = '??' and d2.value = 'Joe Bloggs'
GROUP BY `users`.`ID`
Messy isn't it? Bet you can't wait to go for, four or five values. Or think about (Forename = Joe Or surname = Bloggs) and City = London...
I'm looking for a more efficient way to build this query (double subqueries make me cringe):
SELECT contact_id FROM (
SELECT * FROM (
SELECT mr.contact_id, di.district
FROM recipients mr
JOIN address a ON mr.contact_id = a.contact_id
JOIN district_values di ON a.id = di.entity_id
WHERE mr.mid = 29
ORDER BY di.district DESC ) addrSingle
GROUP BY mr.contact_id ) addrNull
WHERE di.district IS NULL
Let me explain what's going on here.
Recipients holds a list of contacts. Each contact may have multiple addresses. Each address has a related district_values table. I need to retrieve contacts where the district_values.district column is null for ALL addresses.
For example:
Contact A
Address 1.district = 4
Address 2.district = null
= don't include
Contact B
Address 1.district = null
= include
Contact C
Address 1.district = null
Address 2.district = 3
= don't include
The logic of my existing query is as follows:
retrieve contacts with related addresses and districts, order so that any addresses with a non null value are ordered first
apply group by so i reduce to a single contact record and if addresses with a district are retained
apply where clause to remove addresses with at least one district value
It works -- it's just a bit ugly.
You could try this, use LEFT JOIN and count the related record which is zero.
SELECT mr.contact_id
FROM recipients mr
LEFT JOIN address a ON mr.contact_id = a.contact_id
LEFT JOIN district_values di ON a.id = di.entity_id
WHERE mr.mid = 29
GROUP BY mr.contact_id
HAVING COUNT(a.*) = 0 AND COUNT(di.*) = 0