In my tables I have for example
CountyID,County and CityID in the county table and in the city table I have table I have for example
City ID and City
How do I create a report that pulls the County from the county table and pulls city based upon the cityid in the county table.
Thanks
Since this is quite a basic question, I'll give you a basic answer instead of the code to do it for you.
Where tables have columns that "match" each other, you can join them together on what they have in common, and query the result almost as if it was one table.
There are also different types of join based on what you want - for example it might be that some rows in one of the tables you're joining together don't have a corresponding match.
If you're sure that a city will definitely have a corresponding county, try inner joining the two tables on their matching column CityID and querying the result.
The obvious common link between both tables is CityID, so you'd be joining on that. I think you have the data organized wrong though, I'd put CountryID in the City table rather than CityID in the country table. Then, based on the CountryID selected, you can limit your query of the City table based on that.
To follow in context of Bridge's answer, you are obviously new to SQL and there are many places to dig up how to write them. However, the most fundamental basics you should train yourself with is always apply the table name or alias to prevent ambiguity and try to avoid using column names that might be considered reserved words to the language... they always appear to bite people.
That said, the most basic of queries is
select
T1.field1,
T1.field2,
etc with more fields you want
from
FirstTable as T1
where
(some conditional criteria)
order by
(some column or columns)
Now, when dealing with multiple tables, you need the JOINs... typically INNER or LEFT are most common. Inner means MUST match in both tables. LEFT means must match the table on the left side regardless of a match to the right... ex:
select
T1.Field1,
T2.SomeField,
T3.MaybeExistsField
from
SomeTable T1
Join SecondTable T2
on T1.SomeKey = T2.MatchingColumnInSecondTable
LEFT JOIN ThirdTable T3
on T1.AnotherKey = T3.ColumnThatMayHaveTheMatchingKey
order by
T2.SomeField DESC,
T1.Field1
From these examples, you should easily be able to incorporate your tables and their relationships to each other into your results...
Related
I have two tables of world countries Independence Day and I wanted to combine them into one table with a distinct id, but they are using different Primary keys, any suggestions will be appreciated.
Summary of request: How to combine two tables with different Primary Keys but the other fields in common and removing duplicate fields ideally Hash Match and removing duplicates
Expected Results this will include all the unique countries in both tables, please one table may have more countries and we want to make sure we take all the distinct countries from each table. Ideally, the solution will be likely to be of like Hash Match operator in SQL which implements several different logical operations that all use an in-memory hash table for finding matching data. Many thanks in advance
The image of two tables which needs combining.
You seem to want full join:
select a.*, b.* -- select the columns you want
from a full join
b
on a.country = b.country;
If you want to assign a new unique id use row_number():
select row_number() over (order by coalesce(a.country, b.country)) as new_id,
a.*, b.* -- select the columns you want
from a full join
b
on a.country = b.country;
I need to brind a lot of columns from several tables using LEFT JOIN. My starting point is the orders table and I bring the vendor name from the "Address_table". Then I add another table with order details and then the shipping information of each order detail.
My problem is that I need to bring a different record from "Address_table" to refer onether id's detailed in shipment table as of "origin_id" and "destination_id".
In other words, "address_id", "origin_id" and "destination_id" are all records from "Address_table". I brought the first one related to the vendor, how can I retrieve the other two?
Example
Thanks in advance
Your question is not exactly clear in terms of the tables and their relationships. It is, however, clear what the problem is. You need to join against the same table twice using different columns.
In order to do that you need to use table aliases. For example, you can do:
select *
from shipment s
left join address_table a on a.address_id = s.origin_id
left join address_table b on b.address_id = s.destination_id
In this example the table address_table is joined twice against the table shipment; the first time we use a as an alias, the second time b. This way you can differentiate how to pick the right columns and make the joins work as you need them to.
I have several tables with a bunch of fields and I need a Query that includes ALL the fields from two tables (JOINs). The result should have consistent naming scheme for the fields, that survives when I add fields to the source table.
To always select all fields of a table I can use the * operator. But when I join two tables using the *, it prepends the fields that occur in both tables (and only those) with the table name.
SELECT kids.*, parents.* FROM parents INNER JOIN kids ON parents.ID = kids.ParentID;
gives me
kids.name, birthday, school, parents.name, address ...
When I add a birthday column to the parents table I get
kids.name, kids.birthday, school, parents.name, parents.birthday, address ...
And I have to update birthday to kids.birthday everywhere.
Is there a way to prepend all column names in the beginning?
So I'd get
kids.name, kids.birthday, kids.school, parents.name, parents.address ...
in the first place?
So I have three tables: companies, addresses and company_address.
For optimization reasons I need to copy city column from addresses table to companies table. Relation between companies and addresses is many to one (as many companies can occupy same address). They are connected through company_address table, consisting of address_id and company_id columns.
I found this solution for case without intermediate table: How to copy one column of a table into another table's column in PostgreSQL comparing same ID
Trying to modify query I came up with:
UPDATE company SET company.city=foo.city
FROM (
SELECT company_address.company_id, company_address.address_id, address.city
FROM address LEFT JOIN company_address
ON address.id=company_address.address_id
) foo
WHERE company.id=foo.company_id;
but it gives error:
ERROR: column "company" of relation "company" does not exist
I cant figure out what is going on. I'll be grateful for any ideas.
You don't need a subquery for that. Also, refer in the SET clause to your table columns without preceding with table name.
I believe that since your WHERE condition includes joined table, it should be INNER JOIN instead of a LEFT JOIN.
UPDATE company c
SET city = a.city
FROM address a
INNER JOIN company_address ca ON a.id = ca.address_id
WHERE c.id = ca.company_id
Note how using aliases for table names shortens the code and makes it readable at the very first glance.
You're right syntactically, you just don't need the table name at the beginning of the update statement:
UPDATE company SET city=foo.city
FROM (
SELECT company_address.company_id, company_address.address_id, address.city
FROM address LEFT JOIN company_address
ON address.id=company_address.address_id
) foo
WHERE company.id=foo.company_id;
Say you have these tables:
PHARMACY(**___id_pharmacy___**, name, addr, tel)
PHARMACIST(**___Insurance_number___**, name, surname, qualification, **id_pharmacy**)
SELLS(**___id_pharmacy___**, **___name___**, price)
DRUG(**___Name___**, chem_formula, **id_druggistshop**)
DRUGGISTSHOP(**___id_druggistshop___**, name, address)
I think this will be more specific.
So, I'm trying to construct an SQL statement, in which I will fetch the data from id_pharmacy and name FROM PHARMACY, the insurance_number, name, and surname columns from PHARMACIST, for all the pharmacies that sell the drug called Kronol.
And that's basically it. I know I'm missing the relationships in the code I wrote previously.
Note: Those column names which have underscores left and right to them are underlined(Primary keys).
The query you've written won't work in any DBMS that I know of.
You'll most likely want to use some combination of JOINs.
Since the exact schema isn't provided, consider this pseudo code, but hopefully it will get you on the right track.
SELECT PH.Ph_Number, PH.Name, PHCL.Ins_Number, PHCL.Name, PHCL.Surname
FROM PH
INNER JOIN PHCL ON PHCL.PH_Number = PH.Ph_Number
INNER JOIN MLIST ON MLIST.PH_Number = PH.PH_Number
WHERE MLIST.Name = "Andy"
I've obviously assumed some relationships between tables that may or may not exist, but hopefully this will be pretty close. The UNION operator won't work because you're selecting different columns and a different number of columns from the various tables. This is the wrong approach all together for what you're trying to do. It's also worth mentioning that a LEFT JOIN may or may not be a better option for you, depending on the exact requirements you're trying to meet.
Ok, try this query:
SELECT A.id_pharmacy, A.name AS PharmacyName, B.Insurance_number,
B.name AS PharmacistName, B.surname AS PharmacistSurname
FROM PHARMACY A
LEFT JOIN PHARMACIST B
ON A.id_pharmacy = B.id_pharmacy
WHERE A.id_pharmacy IN (SELECT id_pharmacy FROM SELLS WHERE name = 'Kronol')