Table person:
| id | f_name | l_name |
Table sales:
| id | amount | date | itemname |
I have a problem joining the two tables which concat f_name and last_name as fullname column, and joining with table sales. Here id is same on both tables.
Output:
| itemname| date |fullname |
What I have tried:
select *
from
(select
concat(f_name, l_name) as fullname
from
tblperson) p
left join
select itemname, date
from table sales s on s.id = p.id
It should actually be
SELECT table_sales.*, concat(table_person.f_name, table_person.l_name) as fullname
FROM table_person
LEFT JOIN table_sales
ON table_person.id = table_sales.id
have not tested this but that is the syntax
you're missing a field like person_id in your sales table (which references the id field in the person table). You can then use a join to properly join the data together.
You are so close. Try this
select p.*,concat(f_name,l_name)as fullname, s.itemname,s.date, s.amount
from person p left join
sales s on s.id=p.id
Here ia good read on sql join.
https://www.w3schools.com/sql/sql_join.asp
Related
Is it possible to join a table whereby the table name is a value in a column?
Here is a TABLE called food:
id food_name price_table pricing_reference_id
1 | 'apple' | 'daily_price' | 13
2 | 'banana' | 'monthly_price' | 13
3 | 'hotdog' | 'weekly_price' | 17
4 | 'sandwich' | 'monthly_price' | 9
There are three other tables (pricing tables): daily_price, weekly_price, and monthly_price tables.
Side note: Despite their names, the three pricing tables display vastly different kinds of information, which is why the three tables were not merged into one table
Each row in the food table can only be joined with one of the three pricing tables at most.
The following does not work -- it is just to illustrate what I am trying to get at:
SELECT *
FROM food
LEFT JOIN food.price_table ON food.pricing_reference_id = daily_price.id
WHERE id = 1;
Obviously the query does not work. Is there any way that the name of the table in the price_table column could be used as the table name in a join?
I would suggest left joins:
select f.*,
coalesce(dp.price, wp.price, mp.price) as price
from food f left join
daily_price dp
on f.pricing_reference_id = dp.id and
f.pricing_table = 'daily_price' left join
weekly_price wp
on f.pricing_reference_id = wp.id and
f.pricing_table = 'weekly_price' left join
monthly_price mp
on f.pricing_reference_id = mp.id and
f.pricing_table = 'monthly_price' ;
For the columns you reference, you need to use coalesce() to combine the results from the three tables. You say that the tables have different data, so you would need to list the columns separately.
The main reason I recommend this approach is performance. I think the left joins should be faster than any solution that uses union all.
Could you get your expected result using by a derived table with UNION SELECT which has a column of each table name?
SELECT *
FROM food
LEFT JOIN
(
SELECT 'daily_price' AS price_table, * FROM daily_price
UNION ALL SELECT 'monthly_price', * FROM monthly_price
UNION ALL SELECT 'weekly_price', * FROM weekly_price
) t
ON food.price_table = t.price_table AND
food.pricing_reference_id = t.id
ORDER BY food.id;
dbfiddle
I want to join the 2 tables to the first table and group by a vendor name. I have three tables listed below.
Vendors Table
| id | name
|:-----------|------------:|
| test-id | Vendor Name |
VendorOrders Table
| id | VendorId | Details | isActive(Boolean)| price |
|:-----------|------------:|:------------:| -----------------| --------
| random-id | test-id | Sample test | TRUE | 5000
OrdersIssues Table
| id | VendorOrderId| Details. |
|:-----------|--------------:-----------:|
| order-id | random-id | Sample test|
The expected output is to count how many orders belong to a vendor and how many issues belongs to a vendor order.
I have the below code but it's not giving the right output.
SELECT "vendors"."name" as "vendorName",
COUNT("vendorOrders".id) as allOrders,
COUNT("orderIssues".id) as allIssues
FROM "vendors"
LEFT OUTER JOIN "vendorOrders" ON "vendors".id = "vendorOrders"."vendorId"
LEFT OUTER JOIN "orderIssues" ON "orderIssues"."vendorOrderId" = "vendorOrders"."id"
GROUP BY "vendors".id;```
You need the keyword DISTINCT, at least for allOrders:
SELECT v.name vendorName,
COUNT(DISTINCT vo.id) allOrders,
COUNT(DISTINCT oi.id) allIssues
FROM vendors v
LEFT OUTER JOIN vendorOrders vo ON v.id = vo.vendorId
LEFT OUTER JOIN orderIssues oi ON oi.vendorOrderId = vo.id
GROUP BY v.id, v.name;
Consider using aliases instead of full table names to make the code shorter and more readable.
You are joining along two related dimensions. The overall number of rows is the number of issues. But to get the number of orders, you need a distinct count:
SELECT v.*, count(distinct vo.id) as num_orders,
COUNT(oi.vendororderid) as num_issues
FROM vendors v LEFT JOIN
vendorOrders vo
ON v.id = vo.vendorId LEFT JOIN
orderIssues oi
ON oi.vendorOrderId = vo.id
GROUP BY v.id;
Notes:
Table aliases make the query easier to write and to read.
Quoting column and table names makes the query harder to write and read. Don't quote identifiers (you may need to recreate the tables).
Postgres support SELECT v.* . . . GROUP BY v.id assuming that the id is the primary key (actually, it only needs to be unique). This seems like a reasonable assumption.
I have these table in my database :
Ticket
-------------------------------
|ID int PK |
|Paid varchar(50) |
-------------------------------
TicketRow
----------------------------------
|ID int PK |
|TicketID_FK int |
|SHtimeID_FK int |
----------------------------------
I want to fetch the duplicated rows, that have same SHTiemID_FK and have Paid='ok' state in Ticket table, from TicketRow table.
I try this :
select SHtimeID_FK,count(*) as cnt from dbo.TicketRow
group by SHtimeID_FK
having count(*)>1
But i don't know how should i add Ticket table in my result set.
UPDATE :
I also need Ticket.ID in my resultset
If I understand your scenario correctly you can simply join these two tables by a inner join as I suppose TicketRow.TicketID_FK is a foreign key to Ticket table.
select SHtimeID_FK,count(*) as cnt
from dbo.TicketRow as tr inner join dbo.Ticket as t on tr.TicketID_FK=t.ID
where t.Paid='ok'
group by SHtimeID_FK
having count(*)>1
I've 3 Tables
Personel : id, name
Department : id, name
Match_Dept_Per : dept_id, pers_id, workInfo
Foreign Keys :
dept_id --> Department.id
pers_id --> Personel.id
Example Data :
Personel :
1, Emir Civas
2, Sercan Tuncay
Department :
1, Sales
2, Planning
Match_Dept_Per :
1,1,Manager
What I'm trying to do is, listing peoples names, their department names and workInfos like:
ID | Pers. Name | Dept Name | Work Info
---------------------------------------
1 | Emir Civas | Sales | Manager
I can do this with a simple select query:
select p.id, p.name, d.name, m.workInfo
from personel p, department d, match_dept_per m
where p.id = m.pers_id and d.id = m.dept_id;
Here is sample fiddle of my schema and this query.
However what I need is to display other persons that their id's are not inserted to match_dept_per table. And Set "Unknown" As the Null Values. Like:
ID | Pers. Name | Dept Name | Work Info
------------------------------------------
1 | Emir Civas | Sales | Manager
2 | Sercan Tuncay | Unknown | Unknown
Since I'm Using Match_Dept_Per Table, If Personel ID isn't Added, I can't do anything.
Any suggestions ?
Use left outer join to include all persons even if they are not associated with the other tables:
select p.id,
p.name,
ifnull(d.name, 'Unknown') DepName,
ifnull(m.workInfo, 'Unknown') workInfo
from personel p
left outer join match_dept_per m
on p.id = m.pers_id
left outer join department d
on d.id = m.dept_id
Here is a demo fiddle.
As you seem to use MS SQL, you might need to use isnull() instead of ifnull(). But I would ommit that anyway because I think it's better to have a NULL in the code where you use the data (Java, C#, whatever). You can control the output there.
What makes a given table the left table?
Is it that the table is indicated in the "From" part of the query?
Or, is it the left table because it is on the left hand side of the = operator?
Are the following equivalent
SELECT *
FROM left_table
LEFT JOIN right_table ON left_table.right_id = right_table.id
and
SELECT *
FROM left_table
LEFT JOIN right_table on right_table.left_id = left_table.id
???
Thanks
The Left table is the first table in the select. Yes, your two examples are equivalent.
The right table is always the table that you are joining on. So yes, both of your statements are equivalent.
JOIN [Table] ON ...
[Table] is always the right table.
Roughly "left" is the result of everything that appears first in the whole FROM clause when reading from left to right - including the result of other JOINs, sub-queries, VIEWs and STORED PROCEDURES.
Both SQL statements are equivalent because the = operator at the ON part of the JOIN clause is symmetric (if a = b then b = a) so the result is the same no matter the order.
The regular join shows only the lines where the ON clause of the JOIN is true, while the LEFT JOIN shows also the records from "left" if the condition is false (showing NULL for any column from "right" present in the SELECT).
For example:
-- People: -- Car
id | name owner_id | model
---+------------ ---------+------------
1 | Paul 1 | Ferrari
2 | Nancy 2 | Porsche
3 | Arthur NULL | Lamborghini
4 | Alfred 10 | Maserati
> select people.name, car.model from people join car on car.owner_id=people.id;
name | model
---------+--------------
Paul | Ferrari
Nancy | Porsche
2 record(s) found
> select people.name, car.model from people left join car on
car.owner_id=people.id;
name | model
---------+--------------
Paul | Ferrari
Nancy | Porsche
Arthur | NULL
Alfred | NULL
4 record(s) found
> select people.name, car.model from people left join car on
people.id = car.owner_id;
name | model
---------+--------------
Paul | Ferrari
Nancy | Porsche
Arthur | NULL
Alfred | NULL
4 record(s) found
See this for a pretty good walkthrough on joins: http://en.wikipedia.org/wiki/Join_(SQL)
And yes, both statements are equivalent :-)
Yes, it's determined by the side of the JOIN operator the table appears on. Your two examples are indeed equivalent.
CREATE TABLE ORDERS (
ORDERID INT,
CUSTOMERID INT,
ORDERDATE DATE
);
INSERT INTO ORDERS VALUES (10123,10,DATE '16-08-20');
INSERT INTO ORDERS VALUES (10122,11,DATE '14-09-20');
INSERT INTO ORDERS VALUES (10121,12,DATE '10-10-20');
CREATE TABLE CUSTOMERS (
CUSTOMERID INT,
CUSTOMERNAME VARCHAR(20),
COUNTRY VARCHAR(20)
);
INSERT INTO CUSTOMERS VALUES (11 , 'BUDDHA','INDIA');
INSERT INTO CUSTOMERS VALUES (12 , 'JOHNWIK','UNITED STATES');
INSERT INTO CUSTOMERS VALUES (100, 'SERENA','UNITED KINGDOM');
discussing LEFT JOIN query:
select orders.orderid, customers.customername, orders.orderdate from orders
inner join customers on orders.customerid = customers.customerid;
If you want to know exact left and right tables. From left to right the table attached with from is [left] and table attached with join is [right].
Happy Hacking !!!