I am trying to pull up some data.
Here is the setup:
A [school] can have multiple [semester]. Only one [semester] can be active per [school].
The simplified fields per table:
[school] has 'id','title'
[school_semester] has 'id','school_id' (fk), 'semester_id' (fk), 'active', 'start_date', 'end_date'
[semester] has 'id', 'title'
The "school_semester" table holds information for it's specific school/semester. (startdate,enddate,etc).
Anyway, I am simply trying to pull up all schools, and in this query I want to also see that school's current active semester.
Here is my query so far:
SELECT *, `school`.`name` as school_name
FROM (`school`)
LEFT JOIN `school_semester` ON `school`.`id` = `school_semester`.`school_id`
LEFT JOIN `semester` ON `semester`.`id` = `school_semester`.`semester_id`
ORDER BY `school_semester`.`active`
The problem:
This works if a school has semester that is active, but if it does not, it will show one which may be marked as inactive. If I add the statement WHERE school_semester.active = 1, it excludes schools that do not have an active semester..
Any pointers?
move the condition on the joining :
SELECT *, `school`.`name` as school_name
FROM (`school`)
LEFT JOIN `school_semester` ON
`school`.`id` = `school_semester`.`school_id` AND
`school_semester`.`active`
LEFT JOIN `semester` ON `semester`.`id` = `school_semester`.`semester_id`
This way, only the active semesters will be joined to the result.
Add active=1 as part of your join condition.
SELECT *, `school`.`name` as school_name
FROM (`school`)
LEFT JOIN `school_semester` ON `school`.`id` = `school_semester`.`school_id`
AND `school_semester`.`active` = 1
LEFT JOIN `semester` ON `semester`.`id` = `school_semester`.`semester_id`
ORDER BY `school_semester`.`active`
Related
I am trying to get all fields from the product table (*) that have the following set of sub_property:
subprop_name=X
subprop_value=Y
I have the following tables :
https://imgur.com/a/y4LGqMI (couldn't upload the picture because the format was not accepted)
So, for an example, if I have two products which has in their sub_property table a entry like this:
subprop_name=X
subprop_value=Y
I would like to return it. As described by the schema, a product can have multiple sub_property entries!
So far, this is what I have:
SELECT prod_id,prod_name from product WHERE product.prod_id IN
(
SELECT property.product_prod_id FROM property WHERE property.prop_id IN
(
SELECT property_prop_id from sub_property WHERE
(
sub_property.subprop_name="Type de scanner" AND sub_property.subprop_value="par transparence"
)
OR
(
sub_property.subprop_name="Pages/minute maximum" AND subprop_value="8.5 pages"
)
)
)
But obviously, it doesn't work because of the 'OR'.
It returns me all items that have one of the set of sub_property instead of all the products that have all the sets of sub_property.
DATABASE HERE
Using JOIN's and an IN for the tupples could be a simple solution for this.
SELECT p.prod_id, p.prod_name
FROM product p
JOIN property AS prop
ON prop.product_prod_id = p.prod_id
JOIN sub_property AS subprop
ON subprop.property_prop_id = prop.prop_id
WHERE (subprop.subprop_name, subprop.subprop_value) IN (
('Type de scanner', 'par transparence'),
('Pages/minute maximum', '8.5 pages')
)
GROUP BY p.prod_id, p.prod_name
So... I am not sure if it's the correct way to validate two answers, but I got 2 working answers.
This is the first one from #Steff Mächtel using LEFT JOIN (https://stackoverflow.com/a/53915792/5454875)
And the second one is from #Shidersz (see comments below the original question), using INNER JOIN)
"I used and approach using INNER JOIN, is something like this what you need? db-fiddle.com/f/t6RrnhDPQuEamjf2bTxFeX/5"
EDIT
#Shidersz solution doesn't work because it selects all products who as at least one of the condition, wich I don't want. I want the product to have all the conditions.
UPDATE 2:
I would suggest to use LEFT JOIN for each property and each sub_property and then check the value inside WHERE condition:
SELECT product.prod_id, product.prod_name
FROM product
LEFT JOIN property AS property_a ON property_a.product_prod_id = product.prod_id AND
property_a.prop_name = "PROPERTY_GROUP_3"
LEFT JOIN sub_property AS sub_property_a ON sub_property_a.property_prop_id = property_a.prop_id AND
sub_property_a.subprop_name="property_4"
LEFT JOIN property AS property_b ON property_b.product_prod_id = product.prod_id AND
property_b.prop_name = "PROPERTY_GROUP_4"
LEFT JOIN sub_property AS sub_property_b ON sub_property_b.property_prop_id = property_b.prop_id AND
sub_property_b.subprop_name="property_3"
WHERE sub_property_a.subprop_value="value_of_property_4" AND
sub_property_b.subprop_value="value_of_property_3"
GROUP BY product.prod_id
Example: https://www.db-fiddle.com/f/wk344Gt6hm98xEhM4jei92/6
Example with 2 new "KEYS" (Index) for better performance:
ALTER TABLE `property`
... ADD KEY `prop_name` (`prop_name`);
ALTER TABLE `sub_property`
... ADD KEY `subprop_name` (`subprop_name`);
https://www.db-fiddle.com/f/wk344Gt6hm98xEhM4jei92/7
Example with INNER JOIN instead of LEFT JOIN
I see no difference with EXPLAIN on test data, maybe Mysql optimizer handles this internal equal
SELECT product.prod_id, product.prod_name
FROM product
INNER JOIN property AS property_a ON property_a.product_prod_id = product.prod_id AND
property_a.prop_name = "PROPERTY_GROUP_3"
INNER JOIN sub_property AS sub_property_a ON sub_property_a.property_prop_id = property_a.prop_id AND
sub_property_a.subprop_name="property_4" AND
sub_property_a.subprop_value="value_of_property_4"
INNER JOIN property AS property_b ON property_b.product_prod_id = product.prod_id AND
property_b.prop_name = "PROPERTY_GROUP_4"
INNER JOIN sub_property AS sub_property_b ON sub_property_b.property_prop_id = property_b.prop_id AND
sub_property_b.subprop_name="property_3" AND
sub_property_b.subprop_value="value_of_property_3"
GROUP BY product.prod_id
https://www.db-fiddle.com/f/wk344Gt6hm98xEhM4jei92/8
The following query pulls data correctly as expected, however the left join with lnk_cat_isrc table and through that to catalogue table, brings back repeated data if there is more than one item in catalogue which has the same isrcs from isrc table:
SELECT
isrc.ISRC,
isrc.Track_Name,
isrc.ArtistName,
isrc.TitleVersion,
isrc.Track_Time,
`isrc_performer`.`PerformerName` ,
`performer_category`.`PerformerCategory` ,
`isrc_performer`.`PerformerRole` ,
`isrc`.`isrc_ID`,
`isrc_performer`.`Perf_ID`
FROM `isrc`
LEFT JOIN `isrc_performer` ON (isrc.isrc_ID = isrc_performer.isrc_ID)
LEFT JOIN `performer_category` ON (performer_category.PerfCat_ID = isrc_performer.PerfCat_ID)
LEFT JOIN `lnk_cat_isrc` ON (lnk_cat_isrc.isrc_ID = isrc.isrc_ID)
LEFT JOIN `catalogue` ON (catalogue.ID = lnk_cat_isrc.cat_id)
ORDER BY isrc_ID desc LIMIT 0 , 10
";
I cannot use group by on isrc, because the isrc_performer table can have more than one performer to an isrc.
So the relations are like this:
Few items from catalogue table can have several identical items from isrc table. In turn, each isrc can have more than one entry in isrc_performer table.
What I want is to display all corresponding data from isrc_performer in relation to each isrc, but not repeating it for each item from catalogue table.
I also want to display all the rest "empty" isrcs (those which don't have any data in isrc_performer table)
Can you give me any ideas?
P.S. despite I'm not pulling any data from catalogue table itself, I'm using it to search by a catalogue number, when user defines search criteria for $where_condition variable, hence I need to keep it in the query.
i.e. $where_condition = "catalogue.Catalogue LIKE '%test%' OR ISRC LIKE '%test%' OR Track_Name LIKE '%test%' OR ArtistName LIKE '%test%' OR TitleVersion LIKE '%test%' OR PerformerName LIKE '%test%' OR PerformerCategory LIKE '%test%' OR PerformerRole LIKE '%test%'";
------UPD:
trying to graphically represent possible variation in these 3 tables relations:
cat1 - isrc1 - performer1
isrc2 - performer1
- performer2
- performer3
cat2 - isrc2 - performer1
- performer2
- performer3
- isrc3 - performer2
- performer4
cat3 - isrc4
- isrc1 - performer1
UPD (pics added)
Here are screen prints. As you can see on picture 1 there are 9 rows with same isrc number, however there are 3 repeated performers Jason, David, Paul.
This is because 3 different catalogue items have this exact isrc with 3 different performers as per pic 2
= 1(isrc) * 3(catalogue) * 3(performers) = 9 row on output
All I want is that Performers grid would only display 3 rows of this isrc for each performer.
---Rearrange the answer to put the "best" option up top.. .but is all of this for naught.. w/o any data from lnk_cat_isrc or catalogue being returned, why does filtering on catalog make a difference? we're returning all isrc regardless of any filtering because it's a left join...
So this brings into question given sample data what are the expected results.
Possibly more elegant... (but not sure if it would be faster) moving away from exists and simply using a distinct in a subquery so catalog queries always return 1 row per isrc; solving the 1-M problem keeping the left join thereby keeping the isrc records not in the catalog limits.
Return all isrc information performer information if it exists, performer category info if it exists and catalogue information If, and only if it matches the catalog filters.
SELECT isrc.ISRC
, isrc.Track_Name
, isrc.ArtistName
, isrc.TitleVersion
, isrc.Track_Time
,`isrc_performer`.`PerformerName`
,`performer_category`.`PerformerCategory`
,`isrc_performer`.`PerformerRole`
,`isrc`.`isrc_ID`
,`isrc_performer`.`Perf_ID`
FROM `isrc`
LEFT JOIN `isrc_performer`
ON isrc.isrc_ID = isrc_performer.isrc_ID
LEFT JOIN `performer_category`
ON performer_category.PerfCat_ID = isrc_performer.PerfCat_ID
LEFT JOIN (SELECT distinct lnk_cat_isrc.isrc_ID
FROM `lnk_cat_isrc`
INNER JOIN `catalogue`
ON catalogue.ID = lnk_cat_isrc.cat_id
WHERE...) DCat
ON Dcat.isrc_ID = isrc.isrc_ID
ORDER BY isrc_ID desc
LIMIT 0 , 10;
As you pointed out the join is causing the problem. So eliminate the join and use the exists notation. Distinct would also work since you're not selecting any values from catalog; though exists should be faster.
Fast but doesn't include all isrc records... (not sure why the or not exists should bring them back in...)
SELECT isrc.ISRC
, isrc.Track_Name
,isrc.ArtistName
,isrc.TitleVersion
,isrc.Track_Time
,`isrc_performer`.`PerformerName`
,`performer_category`.`PerformerCategory`
,`isrc_performer`.`PerformerRole`
,`isrc`.`isrc_ID`
,`isrc_performer`.`Perf_ID`
FROM `isrc`
LEFT JOIN `isrc_performer`
ON (isrc.isrc_ID = isrc_performer.isrc_ID)
LEFT JOIN `performer_category`
ON (performer_category.PerfCat_ID = isrc_performer.PerfCat_ID)
WHERE EXISTS (SELECT *
FROM `lnk_cat_isrc`
INNER JOIN `catalogue`
ON catalogue.ID = lnk_cat_isrc.cat_id
--and your other criteria
WHERE (lnk_cat_isrc.isrc_ID = isrc.isrc_ID)
)
OR NOT EXISTS (SELECT *
FROM `lnk_cat_isrc`
WHERE lnk_cat_isrc.isrc_ID = isrc.isrc_ID
ORDER BY isrc_ID desc
LIMIT 0 , 10
Or using select distinct simple straight forward; but slow
SELECT isrc.ISRC
, isrc.Track_Name
,isrc.ArtistName
,isrc.TitleVersion
,isrc.Track_Time
,`isrc_performer`.`PerformerName`
,`performer_category`.`PerformerCategory`
,`isrc_performer`.`PerformerRole`
,`isrc`.`isrc_ID`
,`isrc_performer`.`Perf_ID`
FROM `isrc`
LEFT JOIN `isrc_performer`
ON (isrc.isrc_ID = isrc_performer.isrc_ID)
LEFT JOIN `performer_category`
ON (performer_category.PerfCat_ID = isrc_performer.PerfCat_ID)
LEFT JOIN `lnk_cat_isrc`
ON (lnk_cat_isrc.isrc_ID = isrc.isrc_ID)
LEFT JOIN `catalogue`
ON (catalogue.ID = lnk_cat_isrc.cat_id)
--AND (other criteria on catalog here, cause in a where clause you left joins will behave like inner joins)
ORDER BY isrc_ID desc
LIMIT 0 , 10;
I am building an AJAX like search page which allows a customer to select a number filters that will narrow down the search. For instance, a user has selected an 'iPhone 5' and has additional filters for capacity (32GB, 64GB) & colour (black, white..).
The user can only select a single radio box per category (so they could select 32GB & Black).. but they could not select (32GB & 64GB & black as two of these belong to the 'capacity' category).
I have added the schema here on sqlfiddle (please ignore the fact i've removed the primary keys they exist in the proper app they have just been removed along with some other fields/data to minimise the sqlfiddle)
http://sqlfiddle.com/#!2/964425
Can anyone suggest the best way to create the query to do the following:
Get all the prices for device_id '2939' (iPhone 5) which has the 'attributes' of '32GB' AND 'Black'
I currently have this - but this only works when selecting for a single attribute:
// search for device with '64GB' & 'Black' attributes (this currently doesn't return any rows)
SELECT `prices`.*
FROM (`prices`)
LEFT JOIN `prices_attributes` ON `prices_attributes`.`price_id` = `prices`.`id`
WHERE `prices`.`device_id` = '2939'
AND `attribute_option_id` = '19'
AND `attribute_option_id` = '47';
// search for device with '64GB' attribute only (this currently DOES return a row)
SELECT `prices`.*
FROM (`prices`)
LEFT JOIN `prices_attributes` ON `prices_attributes`.`price_id` = `prices`.`id`
WHERE `prices`.`device_id` = '2939'
AND `attribute_option_id` = '19';
Any advice on the database design would be appreciated too
Note: I was thinking to have a new column within the 'prices' table that has the matching attribute_ids serialised - would this be not good for optimisation however (e.g would it be slower than the current method)
Since attribute_option_id is an atomic value, it cannot have two different values for the same row. So your WHERE clause cannot match any record:
SELECT `prices`.*
FROM (`prices`)
LEFT JOIN `prices_attributes` ON `prices_attributes`.`price_id` = `prices`.`id`
WHERE `prices`.`device_id` = '2939'
AND `attribute_option_id` = '19' # Here for one row, attribute_option_id is either 19
AND `attribute_option_id` = '47'; # of '47'. Cannot be the both
Instead of JOIN, you could try a subquery if you feel that is more readable. I think MySQL allow that syntax:
SELECT `prices`.*
FROM `prices`
WHERE `prices`.`device_id` = '2939'
AND EXISTS (SELECT *
FROM prices_attributes
WHERE price_id = `prices`.`id`
AND attribute_option_id IN ('19', '47') )
I don't know how MySQL will optimize the above solution. An alternative would be:
SELECT `prices`.*
FROM `prices`
WHERE `prices`.`id` IN (
SELECT DISTINCT `price_id`
FROM prices_attributes
WHERE attribute_option_id IN ('19', '47')
)
I think you should use the IN operator for the attribute_option_id and you set the values dynamically to the query; Also, using group_by you have only one row per price so in effect you get all the prices. Apart from this, the design is ok.
Here, I have made an example:
SELECT `prices`.*
FROM (`prices`)
LEFT JOIN `prices_attributes` ON `prices_attributes`.`price_id` = `prices`.`id`
WHERE `prices`.`device_id` = '2939'
and `attribute_option_id` in ('19','47')
group by `prices`.`device_id`, `prices`.`price`;
Here, you can also add an order clause to order by price:
order by `prices`.`price` desc;
Another way to solve this would be to use a distinct on price, like this:
select distinct(prices.price)
from prices
where prices.device_id = 2939
and id in (select price_id from prices_attributes where attribute_option_id in (19,47));
Join against the devices_attributes_options table several times, once for each attribute the item must have
Something like this:-
SELECT *
FROM devices a
INNER JOIN prices b ON a.id = b.device_id
INNER JOIN prices_attributes c ON b.id = c.price_id
INNER JOIN devices_attributes_options d ON c.attribute_option_id = d.id AND d.attribute_value = '32GB'
INNER JOIN devices_attributes_options e ON c.attribute_option_id = e.id AND e.attribute_value = 'Black'
WHERE a.id = 2939
As to putting serialised details into a field, this is a really bad idea and would come back to bite you in the future!
SELECT * FROM prices WHERE device_id=2939 AND id IN (SELECT price_id FROM prices_attributes WHERE attribute_option_id IN (19,47));
Is it what you're looking for?
EDIT: sorry, didn't notice you're asking for query using joins
I am trying to just select data from table agency where that agency has entry in the commission table with a certain carrier. My SQL query is returning all entries and 3 times. What am I doing wrong.
$allquery = mysql_query("SELECT agency.ID, agency.agencyname, agency.contdate, agency.physcity FROM agency LEFT JOIN commission ON commission.repnum = agency.repid WHERE agency.repid = '$repid' AND commission.repnum = '$repid' AND commission.carrier = 'Carrier' ")or die(mysql_error())
You are not joining two tables unless you actually specify a join criteria involving columns from each table.
SELECT agency.ID, agency.agencyname, agency.contdate, agency.physcity
FROM agency LEFT JOIN commission ON commision.repid = agency.repid AND commission.carrier = 'Carrier'
Q: Why don't you use an inner join if you want to refer to elements in "commission"?
Q: Why are you doing a join at all??? I don't see how "commission" is linked to "agency". Does "commission" have a "repid" field, too?
Anyway, based on what you've shown, I'd recommend this:
SELECT ID, agencyname, contdate, physcity
FROM agency
where repid = '$repid'
i am developing a PHP/MYSQL search module, where i have to search tables based on many different criteria, i have some 11 tables, and i have used multiple joins to create one single MySQL query and based on WHERE clause i intend to search for specific records, here is the MYSQL Query that i am using.
SELECT
prop.id,
prop.serial,
prop.title,
prop.rating,
prop.addDate,
prop.approve,
prop.status,
prop.user_id as userId,
user_det.email as email,
user_det.name as name,
prop.area_id as areaId,
area.name as areaName,
area.zipCode as zipCode,
area.city_id as cityId,
city.name as cityName,
city.state_id as stateId,
state.name as stateName,
state.country_id as countryId,
country.name as countryName,
prop.subCategory_id as subCategoryId,
subCat.name as subCategoryName,
subCat.category_id as categoryId,
cat.name as categoryName,
prop.transaction_id as transactionId,
trans.name as transactionName,
price.area as landArea,
price.price as priceSqFt,
price.total_price as totalPrice,
features.bedroom,
features.bathroom,
features.balcony,
features.furnished,
features.floorNum,
features.totalFloor
FROM properties prop
LEFT JOIN user_details user_det ON (prop.user_id = user_det.user_id)
LEFT JOIN areas area ON (prop.area_id = area.id)
LEFT JOIN cities city ON (area.city_id = city.id)
LEFT JOIN states state ON (city.state_id = state.id)
LEFT JOIN countries country ON (state.country_id = country.id)
LEFT JOIN subCategories subCat ON (prop.subCategory_id = subCat.id)
LEFT JOIN categories cat ON (subCat.category_id = cat.id)
LEFT JOIN transactions trans ON (prop.transaction_id = trans.id)
LEFT JOIN prop_prices price ON (price.property_id = prop.id)
LEFT JOIN prop_features features ON (features.property_id = prop.id)
although all works well here, i have a situation where i have a table called prop_amenities below are the content of this table.
as the table above have multiple property_id if i query it using JOINS then mostly it will return duplicate records or single record omitting others depending on the type of JOIN i use. so instead i would like to deal it this way.
use the table prop_amenities to only deal with conditions not to return the result.
for example i am searching for a property with amenity id 1,5,9,17 and 24, then it should check if all the records exist in the prop_amenities table, i.e 1,5,9,17 and 24 in this case. and return the appropriate records with all above selected columns.
i am clueless on dealing this situation using MySQL. how do i go on this?
thank you..
You said "check if all the records exist in the prop_amenities table" and that's the key word here.
SELECT ...
FROM properties AS prop
LEFT JOIN ...
WHERE EXISTS (SELECT 1 FROM prop_amenities AS pa WHERE pa.property_id = prop.property_id AND pa.amenity_id = 7);