I have a table with two columns, where none of the columns is unique. I need to auto increment the column number separately for each user.
user | number
1 | 1
2 | 1
1 | 2
3 | 1
The only idea I could come up with is to search for the last number used and manually increment by one. Is there a more efficient way?
Instead of the number field, You can create an auto increment field in the table (I call it id), and get the desired number via a query:
first adding id:
alter table table_name add id int not null IDENTITY(1,1)
you do not need the number field anymore:
alter table table_name drop column number
The query to get number (you can use it to create a view):
select user,
row_number() over(partition by user order by id) as number
from table_name
Search for a user maximum and increment it.
INSERT INTO YOUR_TABLE (user, number)
SELECT (MAX(number) + 1)
FROM YOUR_TABLE
WHERE user = USER_ID
The term of auto-increment covers only the primary key auto-increment. See this page, for more information.
You can do it like in two query:
userno - id of user in integer you want to insert
first write(query 1) i.e if userno already there in table:
insert into table_name
select userno,count(*) from table_name where user = userno
group by user;
if it returns empty row then simply write(query 2) i.e it is a new user to be inserted:
insert into table_name values(userno,1);
Related
I've one table myTable
ID
Content
1
Hello, this is the test content
2
Hi, test content.
I have one list having different values = ["Hello","Hi","Yes","content"]
Now I have to find occurrence of value in myTable-> content column & resultant table have value & count of that value in myTable-> content column (one row of myTable table can have more than one values & use case-insensitive search).
Output be like:
Value
Count
Hello
1
Hi
1
Yes
0
content
2
I want to make optimal SQL server query.
Assuming you are using SQL Server 2016 or above, you could try converting your list to a table like structure, and perform a left join and count on your table.
For instance :
CREATE TABLE MyTable (
ID INT CONSTRAINT PK_MyTable PRIMARY KEY,
Content NVARCHAR(MAX)
);
INSERT INTO MyTable (ID,CONTENT) VALUES
(1,'Hello, this is the test content'),
(2,'Hi, test content.');
DECLARE #MyList NVARCHAR(MAX)
SET #MyList='["Hello","Hi","Yes","content"]';
SELECT
List.Value,
COUNT(MyTable.Content) Count
FROM OPENJSON(#MyList) List --Convert the list to a json
LEFT JOIN MyTable ON '.' + UPPER(MyTable.Content) + '.' LIKE '%[^a-z]' + UPPER(List.Value) +'[^a-z]%'
GROUP BY List.Value;
You can try it on this fiddle.
Please do note that there is margin for improvement, such as full text index instead of this ugly regular expression clause.
See also :
Search for “whole word match” with SQL Server LIKE pattern
I am trying to build a temp table with grouped data from multiple tables (in an SP), I am successful in building the data set however I have a requirement that each grouped row have a unique id. I know there are ways to generate unique ids for each row, However the problem I have is that I need the id for a given row to be the same on each run regardless of the number of rows returned.
Example:
1st run:
ID Column A Column B
1 apple 15
2 orange 10
3 grape 11
2nd run:
ID Column A Column B
3 grape 11
The reason I want this is because i am sending this data up to SOLR and when I do a delta I need to have the ID back for the same row as its trying to re-index
Any way I can do this?
Not sure if this will help, not entirely confident of your wider picture, but ...
As your new data is assembled, log each [column a] value in a table of your own.
Give that table an IDENTITY column to do the numbering for you.
Now you can join any new data sets to your lookup table and you'll have a persistent number for each column A.
You just need to ensure that each time you query new data, you add new values to the lookup table.
create table dbo.myRef(
idx int identity(1,1)
,[A] nvarchar(100)
)
General draft as below ...
--- just simulating some input data here
with cte as (
select 'apple' as [A], 15 as [B]
UNION
select 'orange' as [A], 10 as [B]
UNION
select 'banana' as [A], 4 as [B]
)
select * into #temp from cte;
-- Put any new values into the lookup table
-- and they will be assigned a new index number by the identity column
insert into dbo.myRef([A])
select distinct [A]
from #temp where [A] not in (select [A] from dbo.myRef)
-- now pull your original data for output, joining to the lookup table to get a ref number.
select T.*,R.idx
from #temp T
inner join
oer.myRef R
on T.[A] = R.[A]
Sorry for the late reply, i was stuck with something else, however i solved my own issue.
I built 2 temp tables one with all the data from the various tables (#master) and another temp table (#final) to house all the grouped data with an empty column for ID
Next i did a concat(column1, '-',column2,'-', column3) on 3 columns from the #master and updated the #final table based on the type
this helped me to get the same concat ids on each run
I've deleted some records (more precisely row 4) from a table in a SQL Server database. Now the first column goes like this (1,2,3,5) without row 4:
ID Name
------------
1 Luk
2 Sky
3 Philips
5 Andrey
How can I recreate this table and insert all data again in appropriate order?
Like this:
ID Name
--------
1 Luk
2 Sky
3 Philips
4 Andrey
EDIT:
But if i have another column (number) that is not a key, like this:
ID Number Name
------------
1 1 Luk
2 2 Sky
3 3 Philips
5 5 Andrey
Then can i recreate column Number and Name,
ID Number Name
------------
1 1 Luk
2 2 Sky
3 3 Philips
5 4 Andrey 'Can i do this, and if can HOW?
I would make a pretty strong case for never storing this number, since it is calculated, instead you could just create a view:
CREATE VIEW dbo.YourView
AS
SELECT ID,
Number = ROW_NUMBER() OVER(ORDER BY ID),
Name
FROM dbo.YourTable;
GO
This way after you have deleted rows, your view will already be in sync without having to perform any updates.
If you need to store the value, then almost the same query applies, but just placed inside a common table expression, which is then updated:
WITH CTE AS
( SELECT ID,
Number,
NewNumber = ROW_NUMBER() OVER(ORDER BY ID)
FROM dbo.YourTable
)
UPDATE CTE
SET Number = NewNumber;
You can use dbcc command
DBCC CHECKIDENT('tableName', RESEED, 0)
It would reset identity to 0.
Note it would require to truncate table first.
You can make the ID to auto increment which by default, the starting value for AUTO_INCREMENT is 1, and it will increment by 1 for each new record.
E.g MSSQL uses IDENTITY keyword to auto increment whereas MySQL uses the AUTO_INCREMENT keyword to perform an auto-increment feature.
MSSQL
ID int IDENTITY(1,1) PRIMARY KEY
MySQL
ID int NOT NULL AUTO_INCREMENT
I am trying to mass update a table column with values but I need to get the query to check whether this value already exists. If it does then to make the relevant changes before checking again and updating the table.
The database primarily holds staff information and I need to create a unique username, the script to create the username is :
select upper(LEFT(first_name,1))+LEFT(surname,3)+'1'
from staff_test
If this was used for an example user it would generate a username of ABit1 for user Andrew Bithell. What I need it to do is check to see if there already is a ABit1 username in the STAFF_TEST table and if so change Andrews username to ABit2 as the usernames have to be unique before it moves onto the next user.
I have created another table which lists all the current usernames splitting the existing usernames into 2 columns, so they display in this table as
column1 | column2
------------------
ABit |1
I have experimented with a function and I am now thinking a Merge statement might be the way to go.
Any suggestions are welcomed.
Use row_number can generate all the unique names at once:
select
upper(LEFT(first_name,1))+LEFT(surname,3)+
rtrim(row_number() over (partition by upper(LEFT(first_name,1))+LEFT(surname,3) ))
,first_name
,surname
from staff_test
Perform an up front check to see if there are any clashes:
SELECT UPPER(LEFT(first_name, 1)) + LEFT(surname, 3) + '1' AS username ,
COUNT(1) counter
FROM staff_test
GROUP BY UPPER(LEFT(first_name, 1)) + LEFT(surname, 3) + '1'
HAVING COUNT(1) > 1
ORDER BY COUNT(1) DESC
This will return each username on your staff table, grouped by the username, along with a count of how many occurrences there are of each.
You can either sanitize the data if that's what you're looking to do, otherwise I would suggest, appending an Id column value or some other unique value per record instead of 1 on the end.
How can I show the number of rows in a table in a way that when a new record is added the number representing the row goes higher and when a record is deleted the number gets updated accordingly?
To be more clear,suppose I have a simple table like this :
ID int (primary key) Name varchar(5)
The ID is set to get incremented by itself (using identity specification) so it can't represent the number of row(record) since if I have for example 3 records as:
ID NAME
1 Alex
2 Scott
3 Sara
and I delete Alex and Scott and add a new record it will be:
3 Sara
4 Mina
So basically I'm looking for a sql-side solution for doing this so that I don't change anything else in the source code in multiple places.
I tried to write something to get the job done but it failes. Here it is :
SELECT COUNT(*) AS [row number],Name
FROM dbo.Test
GROUP BY ID, Name
HAVING (ID = ID)
This shows as:
row number Name
1 Alex
1 Scott
1 Sara
while I want it to get shown as:
row number Name
1 Alex
2 Scott
3 Sara
If you just want the number against the rows while selecting the data and not in the database then you can use this
select row_number() over(order by id) from dbo.Test
This will give the row number n for nth row.
Try
SELECT id, name, ROW_NUMBER() OVER (ORDER BY id) AS RowNumber
FROM MyTable
What you want is called an auto increment.
For SQL-Server this is achieved by adding the IDENTITY(1,1) attribute to the table definition.
Other RDBMS use a different syntax. Firebird for example has generators, which do the counting. In a BEFORE-INSERT trigger you would assign the ID-field to the current value of the generator (which will be increased automatically).
I had this exact problem a while ago, but I was using SQL Server 2000, so although row number() is the best solution, in SQL Server 2000, this isn't available. A workaround for this is to create a temporary table, insert all the values with auto increment, and replace the current table with the new table in T-SQL.