How would you list the people from a database that are not from 'London'?
Say the database is:
Cust_id address
1 33 avenue, Liverpool
2 21 street 12345, London
3 469 connection ave, Manchester
I'd like to list the customers that are NOT from London. Here's what I've tried:
select Cust_id from customers where address <> 'London';
Now when I do that, it lists all the customers, regardless of location.
Help would be greatly appericated.
Not ideal but might satisfy your requirements:
select Cust_id from customers
where address NOT LIKE '% London%';
[Note the added space: it assumes you will always precede the city name with a space. '%London%' would match words containing London]
(It might be better if you had a normalised address, i.e. broken into street address, town, city, etc.))
Try this:
select Cust_id from customers where address not like '%London%';
or this:
select Cust_id from customers where not address like '%London%';
Both of these are OK.
For more details on LIKE see e.g. here: SQL LIKE
Related
need some help to construct a PostgreSQL query. I am trying to combine various rows in a Postgres table based on a certain condition.
Here's what the table looks like
Roll_No
Role
Address Type
Address Value
0538
Home
Address Line 1
123 Main Street
0538
Home
Address Line 2
London
0538
Home
Address Line 3
Rogers Street
0538
Home
Address Line 4
United Kingdom
0538
Office
Address Line 1
Adam Land
0538
Office
Address Line 2
Valley Forge PA 19482
0538
Office
Address Line 3
U.S.A
0738
School
Address Line 1
Rogers Street
0738
School
Address Line 2
London
0738
School
Address Line 3
Holland Lane
0738
School
Address Line 4
United Kingdom
I want to concatenate all address values of a specific role (eg. home, school, office) into one column. Address type can contain values like Address Line 1 to 8. Here, Home has Address Line 1 to 4 whereas office has Address Line 1 to 3.
Roll_No
Role
Address Type
Address Value
0538
Home
Home Address
123 Main Street, London, Rogers Street, United Kingdom
0538
Office
Office Address
Adam Land, Valley Forge PA 19482, U.S.A
0738
School
School Address
Rogers Street, London, Holland Lane, United Kingdom
Use array_agg() function for combining column value with comma. Here ORDER BY clause isn't used because address line 4 wouldn't come before address line 1. Extra ORDER BY clause can degrade query performance for a large data sets
-- PostgreSQL
SELECT roll_no, role
, role || ' Address' address_type
, array_to_string(array_agg(address_value), ', ') address_value
FROM test
GROUP BY roll_no, role
ORDER BY roll_no, role;
Please check this url https://dbfiddle.uk/?rdbms=postgres_11&fiddle=e46cf351452a2715258b69afeea5c742
If ORDER BY must needed inside array_agg() function then use the below query
-- after applying order by inside array_agg()
SELECT roll_no, role
, role || ' Address' address_type
, array_to_string(array_agg(address_value order by address_type), ', ') address_value
FROM test
GROUP BY roll_no, role
ORDER BY roll_no, role;
Please check the url https://dbfiddle.uk/?rdbms=postgres_11&fiddle=c196a9a2ca71bd886e4750b935d23040
If same address stored for multiple address line of a particular role for specific roll_no then DISTINCT keyword will use inside array_agg().
-- after applying distinct inside array_agg()
SELECT roll_no, role
, role || ' Address' address_type
, array_to_string(array_agg(DISTINCT address_value), ', ') address_value
FROM test
GROUP BY roll_no, role
ORDER BY roll_no, role;
Please check this url https://dbfiddle.uk/?rdbms=postgres_11&fiddle=e4f0de7c37e003133e2539149db245f8
You may use ARRAY_AGG() inside ARRAY_TO_STRING() but with caution. Because generally, SQL tables are unordered sets. Hence explicitly mentioning ORDER BY inside array_agg() is very very important.
Code:
SELECT
Roll_No,
role,
role || ' address' AS address_type,
array_to_string(array_agg(addressvalue ORDER BY roll_no, role, addresstype), ', ') as address_value
FROM t
GROUP BY Roll_No, role
ORDER BY roll_no, role, address_value
Look at the db<>fiddle. Take a look how results vary with and without ORDER BY inside array_agg().
Looking into my notes for introduction to databases, I have stumbled upon a case that i do not understand (Between except and distinct).
It says so in my notes that:
The two queries below have the same results, but this will not be the case in general.
First query:
Select c.first_name,c.last_name,c.email
FROM customers as c
WHERE c.country = 'Japan'
EXCEPT
Select c.first_name,c.last_name,c.email
FROM customers as c
WHERE c.last_name LIKE 'D%';
Second query:
Select DISTINCT c.first_name,c.last_name,c.email
FROM customers as c
WHERE c.country = 'Japan' AND NOT (c.last_name LIKE 'D%');
Could anyone provide me some insights as to what are cases whereby the results would differ?
Number 1 selects first, last & email from customers who are from Japan and whose last names do not start with D.
Number 2 selects first, last & email, where no two records have all 3 fields the same, where the customers are from Singapore and their last names do not begin with D.
I suppose I can imagine a table where these would yield the same results, but I don't think it would ever appear except in very contrived circumstances.
Joe Smith jsmith#abc.com Japan
Joe Smith jsmith#abc.com Singapore
Would be one of them. Both queries would yield Joe Smith jsmith#abc.com. Another case would be if no-one was from either country or everyone's last name started with D, then they would both yield nothing.
None of this is tested, and the EXCEPT statement is something I've read about but never had occasion to use.
The first is looking at Japan, the second at Singapore, so I don't see why these would generally -- or specifically -- return the same data.
Even if the countries were the same you have another issue with NULL values. So, if your data looks like this:
first_name last_name email country
xxx NULL a Japan
Your first query would return the row. The second would not.
i've got a simple sql question:
I want to get all Customers(more precise: their name and their balance) working in a sector ending with E. I Want to order my results alphabetically by name. Therefore my query is:
SELECT Name,Balance FROM customer WHERE sector LIKE '%E' ORDER BY Name
, which is giving me false results.
I tested it by looking up which sectors exist:
SELECT Distinct(Sector) FROM Kunde
giving me:
Sector
----------
AUTOMOBILE
BUILDING
FURNITURE
HOUSEHOLD
MACHINERY
Now i tried using a query like
SELECT Distinct(Sector) FROM customer WHERE Sector LIKE '%E'
only giving me:
Sector
----------
AUTOMOBILE
It's probably me being stupid here, but why w'ont the last query give me AUTOMOBILE and FURNITURE? I don't see the problem. I'm using DB2 if thats important.
Thank you!
In case of trailing spaces, remove it :
SELECT Distinct(Sector)
FROM customer
WHERE RTRIM(Sector) LIKE '%E'
I am using PL/SQL v7.1
I am trying to find all address records where the country name has been entered in one of the address line fields, and also the country field.
The problem is that the country details have not been entered consistently eg.
addr4 addr5 country
---------- ---------- ---------------
JERSEY UK(JERSEY)
IRELAND REPUBLIC OFIRELAND
DOUGLAS ISLE OF MAN UK(ISLE OF MAN)
So, I need to find the records where ANY PART of the Country field is also found in either addr4 or addr5.
I started with this
SELECT *
FROM test_addresses
WHERE addr4||addr5 LIKE '%'||country||'%'
I know this doesn't work because it will, taking the 1st record as an example, check if 'UK(JERESEY)' is found in addr4||addr5 and ,so, no match will be found. But how do I make it check if 'JERSEY' is found in addr4||addr5
Try this way:
SELECT *
FROM test_addresses
WHERE (addr4 is not null and country like '%'||addr4||'%')
or (addr5 is not null and country like '%'||addr5||'%')
Sql Fiddle Demo
I don't know so much about plsql
but I think your query is backwards, try this.
SELECT *
FROM test_addresses
WHERE country LIKE '%'||addr4||'%'
or country LIKE '%'||addr5||'%'
I need to run a query that would pull information from a field that has 2 types of data .
Field is address and has 123 avenue as data and bb#yahoo.com.
I need to make 2 fields one for email and one STaddress from table customer and field address?
anyone can i assis..
its access and vb query
I thought of this
Select customer.address from customer where address like "#"
but still i need to display the the data of address field to 2 different fields...
Here is the query that fetches the two different fields:
select iif(field like '*#*', field, NULL) as email,
iif(field like '*#*, NULL, field) as address
from t
The usage of like in Access is a bit different from other databases.
I would suggest that you create a view with this logic. If you actually want to modify the table, you will have to add columns and populate them with logic like the above.
Based on this question and your duplicate question, I understand your table has a field which includes both the street address and email address and you want to split those into separate fields.
So your table includes this ...
YourField
------------------------------
1234 ave willie haha#yahoo.com
123 avenue bb#yahoo.com
And you want this ...
YourField street_address email_address
------------------------------ --------------- --------------
1234 ave willie haha#yahoo.com 1234 ave willie haha#yahoo.com
123 avenue bb#yahoo.com 123 avenue bb#yahoo.com
If that is correct, you can use the InstrRev() function to determine the position of the last space in YourField. Everything before the last space is the street address; everything after is the email address.
SELECT
y.YourField,
Left(y.YourField, InstrRev(y.YourField, ' ') -1) AS street_address,
Mid(y.YourField, InstrRev(y.YourField, ' ') +1) AS email_address
FROM YourTable AS y;
You may need to add a WHERE clause to ensure the query only tries to evaluate rows which include your expected YourField value patterns.
Try something like this:
select *,
(case locate('#', address) when 0 then null else address) as email,
(case locate('#', address) when 0 then address else null) as street
from table;
You'd probably need to adjust the name of "locate" function - I'm not sure if it is the same in access database.
If you have a street address and then an email address in the same field, and want to split them, then use this.
We'll call your original field Addy, and the new fields Street & Email.
SELECT Left(Addy, InStrRev(Addy, " ", InStr(Addy, "#")) - 1) AS Street, mid(Addy, InStrRev(Addy, " ", InStr(Addy, "#")) + 1) AS Email.
What this does is look for the #, then go backwards and look for the first space. The first function takes every left of that space and calls it Street, while the second function takes everything to the right.
The function is really 3 functions nested together. To really understand what it's doing, I'll dissect it.
I = InStr(Addy, "#")
J = InStrRev(Addy, " ", I)
Street = Left(Addy,J-1)