JOINing Three SQL Tables? - mysql

I have a working SQL query, but I need to grab another piece of data from a third table in the query for ease of use, but have been unable to grab it.
Every table is basically tied together by tenant_id
(I apologize for the bad structure, I didn't create the DB)
TABLE: tenant_statements
tenant_id balance property date
TABLE: leases
lease_id tenant_id property unit_number
TABLE: tenants
tenant_id first_name last_name global_comment
My current query:
SELECT *
FROM tenant_statements t
INNER JOIN (
SELECT *
FROM leases
GROUP BY tenant_id
ORDER BY lease_id
)l ON t.tenant_id = l.tenant_id
WHERE t.date = '$date'
AND t.property = '$property'
ORDER BY t.balance DESC
This give's me the appropriate response for joining the two tables: leases and tenant_statements. $date and $property are set via a PHP variable loop and used for presentation.
What I am attempting to do is also grab tenants.global_comment and have it added each result.
the ideal output will be:
tenant_statements t: t.balance, t.date
leases l: l.property, l.unit_number
tenants x: x.first_name, x.last_name, x.global_comment
All in one query.
Can anyone point me in to the right direction? Thank you!

How about something like
SELECT *
FROM tenant_statements t INNER JOIN
(
SELECT *
FROM leases
GROUP BY tenant_id
ORDER BY lease_id
)l ON t.tenant_id = l.tenant_id INNER JOIN
tenants ts ON t.tenant_id = ts.tenant_id
WHERE t.date = '$date'
AND t.property = '$property'
ORDER BY t.balance DESC

Although each join specification joins only two tables, FROM clauses can contain multiple join specifications. This allows many tables to be joined for a single query.
SELECT t.tenant_id,
t.balance,
l.unit_number,
l.property
x.first_name, x.last_name, x.global_comment
fROM tenant_statements t
INNER JOIN leases l ON l.tenant_id = t .tenant_id
INNER JOIN tenants x on x.tenant_id = t.tenant_id

Related

Inner query or multiple queries which would be result in better performance for mysql?

Inner query:
select up.user_id, up.id as utility_pro_id from utility_pro as up
join utility_pro_zip_code as upz ON upz.utility_pro_id = up.id and upz.zip_code_id=1
where up.available_for_survey=1 and up.user_id not in (select bjr.user_id from book_job_request as bjr where
((1583821800000 between bjr.start_time and bjr.end_time) and (1583825400000 between bjr.start_time and bjr.end_time)))
Divided in two queries:
select up.user_id, up.id as utility_pro_id from utility_pro as up
join utility_pro_zip_code as upz ON upz.utility_pro_id = up.id and upz.zip_code_id=1
Select bjr.user_id as userId from book_job_request as bjr where bjr.user_id in :userIds and (:startTime between bjr.start_time and bjr.end_time) and (:endTime between bjr.start_time and bjr.end_time)
Note:
As per my understanding, when single query will be executed using inner query it will scan all the data of book_job_request but while using multiple queries rows with specified user ids will be checked.
Any other better option for the same operation other than these two is also appreciated.
I expect that the query is supposed to be more like this:
SELECT up.user_id
, up.id utility_pro_id
FROM utility_pro up
JOIN utility_pro_zip_code upz
ON upz.utility_pro_id = up.id
LEFT
JOIN book_job_request bjr
ON bjr.user_id = up.user_id
AND bjr.end_time >= 1583821800000
AND bjr.start_time <= 1583825400000
WHERE up.available_for_survey = 1
AND upz.zip_code_id = 1
AND bjr.user_id IS NULL
For further help with optimisation (i.e. which indexes to provide) we'd need SHOW CREATE TABLE statements for all relevant tables as well as the EXPLAIN for the above
Another possibility:
SELECT up.user_id , up.id utility_pro_id
FROM utility_pro up
JOIN utility_pro_zip_code upz ON upz.utility_pro_id = up.id
WHERE up.available_for_survey = 1
AND upz.zip_code_id = 1
AND bjr.user_id IS NULL
AND NOT EXISTS( SELECT 1 FROM book_job_request
WHERE user_id = up.user_id
AND end_time >= 1583821800000
AND start_time <= 1583825400000 )
Recommended indexes (for my NOT EXISTS and for Strawberry's LEFT JOIN):
book_job_request: (user_id, start_time, end_time)
upz: (zip_code_id, utility_pro_id)
up: (available_for_survey, user_id, id)
The column order given is important. And, no, the single-column indexes you currently have are not as good.

Left join sql query

I want to get all the data from the users table & the last record associated with him from my connection_history table , it's working only when i don't add at the end of my query
ORDER BY contributions DESC
( When i add it , i have only the record wich come from users and not the last connection_history record)
My question is : how i can get the entires data ordered by contributions DESC
SELECT * FROM users LEFT JOIN connections_history ch ON users.id = ch.guid
AND EXISTS (SELECT 1
FROM connections_history ch1
WHERE ch.guid = ch1.guid
HAVING Max(ch1.date) = ch.date)
The order by should not affect the results that are returned. It only changes the ordering. You are probably getting what you want, just in an unexpected order. For instance, your query interface might be returning a fixed number of rows. Changing the order of the rows could make it look like the result set is different.
I will say that I find = to be more intuitive than EXISTS for this purpose:
SELECT *
FROM users u LEFT JOIN
connections_history ch
ON u.id = ch.guid AND
ch.date = (SELECT Max(ch1.date)
FROM connections_history ch1
WHERE ch.guid = ch1.guid
)
ORDER BY contributions DESC;
The reason is that the = is directly in the ON clause, so it is clear what the relationship between the tables is.
For your casual consideration, a different formatting of the original code. Note in particular the indented AND suggests the clause is part of the LEFT JOIN, which it is.
SELECT * FROM users
LEFT JOIN connections_history ch ON
users.id = ch.guid
AND EXISTS (SELECT 1
FROM connections_history ch1
WHERE ch.guid = ch1.guid
HAVING Max(ch1.date) = ch.date
)
We can use nested queries to first check for max_date for a given user and pass the list of guid to the nested query assuming all the users has at least one record in the connection history table otherwise you could use Left Join instead.
select B.*,X.* from users B JOIN (
select A.* from connection_history A
where A.guid = B.guid and A.date = (
select max(date) from connection_history where guid = B.guid) )X on
X.guid = B.guid
order by B.contributions DESC;

MySQL Sub Sub Query seems to loop

I have this MySQL query to get the total amount of only the first invoice for each client on a given month:
SELECT SUM(InvoiceProductTotal)
FROM tblinvoiceproduct
WHERE InvoiceID IN (
SELECT MIN(tblinvoice.InvoiceID) AS InvoiceID
FROM tblinvoice
WHERE tblinvoice.ClientID IN (
SELECT tblclient.ClientID
FROM tblclient
LEFT JOIN tblenquiry ON tblclient.EnquiryID = tblenquiry.EnquiryID
WHERE NOT tblclient.EnquiryID IS NULL
AND YEAR(EnquiryDate) = 2014
AND MONTH(EnquiryDate) = 9
)
GROUP BY tblinvoice.ClientID
);
When I run it, it seems to loop forever. If I remove the first part it gives me the list of invoices instantly. Am sure it is a small syntax detail but haven't been able to figure out what the problem is after nearly one hour trying to fix it.
Your assistance is appreciated.
This query can probably be done in a better way without all the sub queries as well, just I'm not so experienced with sub queries. :)
Solution was given but I should have included the full query rather than just the part I was having trouble with. The full query is:
SELECT AdvertisingID, AdvertisingTitle, AdvertisingYear,
AdvertisingMonth, AdvertisingTotal, AdvertisingVisitors,
IFNULL(
(SELECT SUM(InvoiceProductTotal)
FROM tblinvoiceproduct
JOIN
(SELECT MIN(tblinvoice.InvoiceID) AS InvoiceID
FROM tblinvoice
JOIN
(SELECT DISTINCT tblclient.ClientID
FROM tblclient
JOIN tblenquiry ON tblclient.EnquiryID = tblenquiry.EnquiryID
WHERE YEAR(tblenquiry.EnquiryDate)=tbladvertising.AdvertisingYear
AND MONTH(tblenquiry.EnquiryDate)=tbladvertising.AdvertisingMonth)
AS inq
ON tblinvoice.ClientID = inq.ClientID
GROUP BY tblinvoice.ClientID) AS inq2
ON tblinvoiceproduct.InvoiceID = inq2.InvoiceID)
, 0)
FROM tbladvertising
ORDER BY AdvertisingYear DESC, AdvertisingMonth DESC, AdvertisingTitle;
Now the problem is that the column with the sub query has no access to "tbladvertising.AdvertisingYear" or "tbladvertising.AdvertisingMonth"
A commenter mentioned that it's hard to understand what you're trying to do here. I agree. But I will take the risk of trying to puzzle it out.
As usual with this sort of query, it's helpful to take advantage of the structured part of structured query language, and try to build this up piece by piece. That's the secret to creating complex queries that actually do what you want them to do.
Your innermost query is this:
SELECT tblclient.ClientID
FROM tblclient
LEFT JOIN tblenquiry ON tblclient.EnquiryID = tblenquiry.EnquiryID
WHERE NOT tblclient.EnquiryID IS NULL
AND YEAR(EnquiryDate) = 2014
AND MONTH(EnquiryDate) = 9
It is saying, "give me the list of ClientID values which have enquiries in September 2014. There's a more efficient way to do this:
SELECT DISTINCT tblclient.ClientID
FROM tblclient
JOIN tblenquiry ON tblclient.EnquiryID = tblenquiry.EnquiryID
WHERE tblenquiry.EnquiryDate >= '2014-09-01'
AND tblenquiry.EnquiryDate < '2014-09-01' + INTERVAL 1 MONTH
Two changes here: First, the NOT ... IS NULL search is unnecessary because if the item you're searching on is null, there's no way for your EnquiryDate to be valid. So we just change the LEFT JOIN to an ordinary inner JOIN and get rid of the otherwise expensive NULL scan.
Second, we recast the date matching as a range scan, so it can use an index on tbl.EnquiryDate.
Cool.
Next, we have this query level.
SELECT MIN(tblinvoice.InvoiceID) AS InvoiceID
FROM tblinvoice
WHERE tblinvoice.ClientID IN (
/* that list of Client IDs from the innermost query */
)
GROUP BY tblinvoice.ClientID
That is pretty straightforward. But MySQL isn't too swift with IN () clauses, so let's recast it in the form of a JOIN as follows:
SELECT MIN(tblinvoice.InvoiceID) AS InvoiceID
FROM tblinvoice
JOIN (
/* that list of Client IDs from the innermost query */
) AS inq ON tblinvoice.ClientID = inq.ClientID
GROUP BY tblinvoice.ClientID
This gets us the list of invoice IDs which were the subject of the first enquiry of the month on behalf of each distinct ClientID. (It's hard for me to figure out the business meaning of this, but I don't understand your business.)
Finally, we come to your outermost query. We can also recast that as a JOIN, like so.
SELECT SUM(InvoiceProductTotal)
FROM tblinvoiceproduct
JOIN (
/* that list of first-in-month invoices */
) AS inq2 ON tblinvoiceproduct.InvoiceID = inq2.InvoiceID
So, this all expands to:
SELECT SUM(InvoiceProductTotal)
FROM tblinvoiceproduct
JOIN (
SELECT MIN(tblinvoice.InvoiceID) AS InvoiceID
FROM tblinvoice
JOIN (
SELECT DISTINCT tblclient.ClientID
FROM tblclient
JOIN tblenquiry ON tblclient.EnquiryID = tblenquiry.EnquiryID
WHERE tblenquiry.EnquiryDate >= '2014-09-01'
AND tblenquiry.EnquiryDate < '2014-09-01' + INTERVAL 1 MONTH
) AS inq ON tblinvoice.ClientID = inq.ClientID
GROUP BY tblinvoice.ClientID
) AS inq2 ON tblinvoiceproduct.InvoiceID = inq2.InvoiceID
That should do the trick for you. In summary, the big optimizing changes are
using a date range scan.
eliminating the NOT ... IS NULL criterion.
recasting your IN clauses as JOIN clauses.
The next step will be to create useful indexes. A compound index (EnquiryDate, EnquiryID) on your tblenquiry is very likely to help a lot. But to be sure you'll need to do some EXPLAIN analysis.
What if you modify your above posted query, to replace the subquery with JOIN (INNER JOIN) like below. Give it a try.
SELECT SUM(InvoiceProductTotal)
FROM tblinvoiceproduct
JOIN
(
SELECT MIN(ti.InvoiceID) as MinInvoice
FROM tblinvoice ti
JOIN
(
SELECT tblclient.ClientID
FROM tblclient
LEFT JOIN tblenquiry
ON tblclient.EnquiryID = tblenquiry.EnquiryID
WHERE NOT tblclient.EnquiryID IS NULL
AND YEAR(EnquiryDate) = 2014
AND MONTH(EnquiryDate) = 9
) tab
on ti.ClientID = tab.ClientID
GROUP BY ti.ClientID
) tab1
on tblinvoiceproduct.InvoiceID = tab1.MinInvoice

MySQL Inner Join with where clause sorting and limit, subquery?

Everything in the following query results in one line for each invBlueprintTypes row with the correct information. But I'm trying to add something to it. See below the codeblock.
Select
blueprintType.typeID,
blueprintType.typeName Blueprint,
productType.typeID,
productType.typeName Item,
productType.portionSize,
blueprintType.basePrice * 0.9 As bpoPrice,
productGroup.groupName ItemGroup,
productCategory.categoryName ItemCategory,
blueprints.productionTime,
blueprints.techLevel,
blueprints.researchProductivityTime,
blueprints.researchMaterialTime,
blueprints.researchCopyTime,
blueprints.researchTechTime,
blueprints.productivityModifier,
blueprints.materialModifier,
blueprints.wasteFactor,
blueprints.maxProductionLimit,
blueprints.blueprintTypeID
From
invBlueprintTypes As blueprints
Inner Join invTypes As blueprintType On blueprints.blueprintTypeID = blueprintType.typeID
Inner Join invTypes As productType On blueprints.productTypeID = productType.typeID
Inner Join invGroups As productGroup On productType.groupID = productGroup.groupID
Inner Join invCategories As productCategory On productGroup.categoryID = productCategory.categoryID
Where
blueprints.techLevel = 1 And
blueprintType.published = 1 And
productType.marketGroupID Is Not Null And
blueprintType.basePrice > 0
So what I need to get in here is the following table with the columns below it so I can use the values timestamp and sort the entire result by profitHour
tablename: invBlueprintTypesPrices
columns: blueprintTypeID, timestamp, profitHour
I need this information with the following select in mind. Using a select to show my intention of the JOIN/in-query select or whatever that can do this.
SELECT * FROM invBlueprintTypesPrices
WHERE blueprintTypeID = blueprintType.typeID
ORDER BY timestamp DESC LIMIT 1
And I need the main row from table invBlueprintTypes to still show even if there is no result from the invBlueprintTypesPrices. The LIMIT 1 is because I want the newest row possible, but deleting the older data is not a option since history is needed.
If I've understood correctly I think I need a subquery select, but how to do that? I've tired adding the exact query that is above with a AS blueprintPrices after the query's closing ), but did not work with a error with the
WHERE blueprintTypeID = blueprintType.typeID
part being the focus of the error. I have no idea why. Anyone who can solve this?
You'll need to use a LEFT JOIN to check for NULL values in invBlueprintTypesPrices. To mimic the LIMIT 1 per TypeId, you can use the MAX() or to truly make sure you only return a single record, use a row number -- this depends on whether you can have multiple max time stamps for each type id. Assuming not, then this should be close:
Select
...
From
invBlueprintTypes As blueprints
Inner Join invTypes As blueprintType On blueprints.blueprintTypeID = blueprintType.typeID
Inner Join invTypes As productType On blueprints.productTypeID = productType.typeID
Inner Join invGroups As productGroup On productType.groupID = productGroup.groupID
Inner Join invCategories As productCategory On productGroup.categoryID = productCategory.categoryID
Left Join (
SELECT MAX(TimeStamp) MaxTime, TypeId
FROM invBlueprintTypesPrices
GROUP BY TypeId
) blueprintTypePrice On blueprints.blueprintTypeID = blueprintTypePrice.typeID
Left Join invBlueprintTypesPrices blueprintTypePrices On
blueprintTypePrice.TypeId = blueprintTypePrices.TypeId AND
blueprintTypePrice.MaxTime = blueprintTypePrices.TimeStamp
Where
blueprints.techLevel = 1 And
blueprintType.published = 1 And
productType.marketGroupID Is Not Null And
blueprintType.basePrice > 0
Order By
blueprintTypePrices.profitHour
Assuming you might have the same max time stamp with 2 different records, replace the 2 left joins above with something similar to this getting the row number:
Left Join (
SELECT #rn:=IF(#prevTypeId=TypeId,#rn+1,1) rn,
TimeStamp,
TypeId,
profitHour,
#prevTypeId:=TypeId
FROM (SELECT *
FROM invBlueprintTypesPrices
ORDER BY TypeId, TimeStamp DESC) t
JOIN (SELECT #rn:=0) t2
) blueprintTypePrices On blueprints.blueprintTypeID = blueprintTypePrices.typeID AND blueprintTypePrices.rn=1
You don't say where you are putting the subquery. If in the select clause, then you have a problem because you are returning more than one value.
You can't put this into the from clause directly, because you have a correlated subquery (not allowed).
Instead, you can put it in like this:
from . . .
(select *
from invBLueprintTypesPrices ibptp
where ibtp.timestamp = (select ibptp2.timestamp
from invBLueprintTypesPrices ibptp2
where ibptp.blueprintTypeId = ibptp2.blueprintTypeId
order by timestamp desc
limit 1
)
) ibptp
on ibptp.blueprintTypeId = blueprintType.TypeID
This identifies the most recent records for all the blueprintTypeids in the subquery. It then joins in the one that matches.

MySQL views cannot have subquery in from, and don't maintain order. How can I create a view from this query?

I'm essentially trying to obtain a resultset with each employee's current title. I'd like to create a view from this for later use, but I find I'm being stumped, and likely missing a simple solution. Here's the query in question, and thanks in advance!
select * from
(SELECT
appointment.employee_id,
title.`name` as title_name
FROM
appointment
INNER JOIN appointment_title ON appointment.id = appointment_title.appointment_id
INNER JOIN title ON appointment_title.title_id = title.id
order by appointment_title.effective_date DESC) tmp group by employee_id
Updated:
SELECT
appointment.employee_id ,
( SELECT title.`name`
FROM appointment_title
INNER JOIN title
ON appointment_title.title_id = title.id
WHERE appointment.id = appointment_title.appointment_id
ORDER BY appointment_title.effective_date DESC
LIMIT 1
) AS title_name
FROM appointment
GROUP BY appointment.employee_id
Another option is to break up the query into two views. The first view will contain the derived table subquery, and the second will simply select from that one:
CREATE VIEW vwEmployee_Inner AS
SELECT
appointment.employee_id,
title.`name` as title_name
FROM
appointment
INNER JOIN appointment_title ON appointment.id = appointment_title.appointment_id
INNER JOIN title ON appointment_title.title_id = title.id
order by appointment_title.effective_date DESC
And then your original view becomes:
CREATE VIEW vwEmployee AS
SELECT * FROM vwEmployee_Inner GROUP BY employee_id