I wonder if anyone can help me achieve this. I have a row of 100 columns, 1st being the primary key. I need to retrieve from each row in my query the primary key column and a HASHBYTES of the entire row, so the results would look like:
PK Hash
000123 HASHVALUE1234567890ETC
I can get the entire row with this select statement:
SELECT hashbytes('sha1', (SELECT * From Table Where PK = 000123 FOR XML RAW))
I cannot however work out how to get the PK and hash together in the same results..
Thanks in advance for your help.
Derek.
Select CompanyPK,
(SELECT hashbytes('sha1',
(SELECT * From Company
Where CompanyPK = 'f5dba28b-ae3b-407a-807c-068acde88298' FOR XML RAW)))
as [Hash]
From Company
Where CompanyPK = 'f5dba28b-ae3b-407a-807c-068acde88298'
Sorry to waste your time :)
Related
I have a logging table that is live which saves my value to a table frequently.
My plan is to take those values and put them on a temporary table with
SELECT * INTO #temp from Block
From there I guess my block table is empty and the logger can keep on logging new values.
The next step is that I want to save them in a existing table. I wanted to use
INSERT INTO TABLENAME(COLUMN1,COLUMN2...) SELECT (COLUMN1,COLUMN2...) FROM #temp
The problem is that the #temp table has duplicates primary keys. And I only want to store the last ID.
I have tried DISTINCT but it didn't work. Could not get ROW_Count to work. Are there any ideas on how I should do it? I wish to make it with as few reads as possible.
Also, in the future I plan to send them to another database, how do I do that on SQL Server? I guess it's something like FROM Table [in databes]?
I couldn't get the blocks to copy. But here goes:
create TABLE Product_log (
Grade char(64),
block_ID char(64) PRIMARY KEY NOT NULL,
Density char(64),
BatchNumber char(64) NOT NULL,
BlockDateID Datetime
);
That is my table i want to store the data in. There I do not wish to have duplicates on the id. The problem is, while logging I get duplicates since I log on change. Lets say that the batchid is 1, if it becomes 2 while logging. I will get a blockid twice, both with batch number 1 and 2. How do I pick the latter?
Hope I explained enough for guidance. While logging they look like this:
id SiemensTiaV15_s71200_BatchTester_NewBatchIDValue_VALUE SiemensTiaV15_s71200_BatchTester_TestWriteValue_VALUE SiemensTiaV15_s71200_BatchTester_TestWriteValue_TIMESTAMP SiemensTiaV15_s71200_MainTank_Density_VALUE SiemensTiaV15_s71200_MainTank_Grade_VALUE
1 00545 S0047782 2020-06-09 11:18:44.583 0 xxxxx
2 00545 S0047783 2020-06-09 11:18:45.800 0 xxxxx
Please use below query,
select * from
(select id, SiemensTiaV15_s71200_BatchTester_NewBatchIDValue_VALUE,SiemensTiaV15_s71200_BatchTester_TestWriteValue_VALUE, SiemensTiaV15_s71200_BatchTester_TestWriteValue_TIMESTAMP, SiemensTiaV15_s71200_MainTank_Density_VALUE,SiemensTiaV15_s71200_MainTank_Grade_VALUE,
row_number() over (partition by SiemensTiaV15_s71200_BatchTester_NewBatchIDValue_VALUE order by SiemensTiaV15_s71200_BatchTester_TestWriteValue_TIMESTAMP desc) as rnk
from table_name) qry
where rnk=1;
INTO #temp FROM Block; INSERT INTO Product_log(Grade, block_ID, Density, BatchNumber, BlockDateID)
selct NewBatchIDValue_VALUE, TestWriteValue_VALUE, TestWriteValue_TIMESTAMP,
Density_VALUE, Grade_VALUE from
(select NewBatchIDValue_VALUE, TestWriteValue_VALUE,
TestWriteValue_TIMESTAMP, Density_VALUE, Grade_VALUE, row_number() over
(partition by BatchTester_NewBatchIDValue_VALUE order by
BatchTester_TestWriteValue_VALUE) as rnk from #temp) qry
where rnk = 1;
I have a Product table which keeps on adding rows with product_id and price . It has millions of rows.
It has a product_id as Primary key like below.
CREATE TABLE ProductPrice(
product_id VARCHAR2(10),
prod_date DATE ,
price NUMBER(8,0) ,
PRIMARY KEY (product_id)
)
Now this has millions of rows and to get the latest price it get a lot of time.
So to manage the latest price, I have created another table which will keep only the latest price with same format.
CREATE TABLE ProductPriceLatest(
product_id VARCHAR2(10),
prod_date DATE ,
price NUMBER(8,0) ,
PRIMARY KEY (product_id)
)
And on every insert on original table, i will write a trigger which will update the row in this table.
But how can i get the newly inserted values inside the trigger body?
I have tried something like this:
CREATE OR REPLACE TRIGGER TRIG_HISTory
AFTER INSERT
on ProductPriceLatest
FOR EACH ROW
DECLARE
BEGIN
UPDATE latest_price
SET price = NEW.price ,
WHERE product_id = NEW.product_id ;
END;
Thanks in advance.
You need to use the :new keyword to differentiate with :old values. Also, better use AFTER trigger:
CREATE OR REPLACE TRIGGER TRIG_HISTORY
AFTER INSERT ON source_table_name
FOR EACH ROW
DECLARE
BEGIN
MERGE INTO dest_table_name d
USING (select :new.price p, :new.product_id p_id from dual) s
ON (d.product_id = s.p_id)
WHEN MATCHED THEN
UPDATE SET d.price = s.p
WHEN NOT MATCHED THEN
INSERT (price, product_id)
VALUES (s.p, s.p_id);
END;
Retrieving the latest price from your first table should be fast if you have the correct index. Building the correct index on your ProductPrice table is a far better solution to your problem than trying to maintain a separate table.
Your query to get the latest prices would look like this.
SELECT p.product_id, p.prod_date, p.price
FROM ProductPrice p
JOIN (
SELECT product_id, MAX(prod_date) latest_prod_date
FROM ProductPrice
GROUP BY product_id
) m ON p.product_id = m.product_id
AND p.prod_date = m.latest_prod_date
WHERE p.product_id = ????
This works because the subquery looks up the latest product date for each product. It then uses that information to find the right row in the table to show you.
If you create a compound index on (product_id, prod_date, price) this query will run almost miraculously fast. That's because the query planner can find the correct index item in O(log n) time or better.
You can make it into a view like this:
CREATE OR REPLACE VIEW ProductPriceLatest AS
SELECT p.product_id, p.prod_date, p.price
FROM ProductPrice p
JOIN (
SELECT product_id, MAX(prod_date) latest_prod_date
FROM ProductPrice
GROUP BY product_id
) m ON p.product_id = m.product_id
AND p.prod_date = m.latest_prod_date;
Then you can use the view like this:
SELECT * FROM ProductPriceLatest WHERE product_id = ???
and get the same high performance.
This is easier, less error-prone, and just as fast as creating a separate table and maintaining it. By the way, DBMS jargon for the table you propose to create is materialized view.
In an interview I was asking to find nth maximum salary without using CTE, top, sub query. I am confused. Is any other way to do.
And another question,
2 tables having identical columns with Identity ID column. When copying records from table1 to table2, the ID values also should be moved. For example, if table1 having the IDs 1,3,5,7.. the same ID values should be moved to table2 ID column.
He is looking for new feature OFFSET.
Query to get 10th salary
SELECT * FROM dbp.Empsalary AS P
ORDER BY P.salary desc
OFFSET 9 ROWS
FETCH NEXT 1 ROWS ONLY
Note: N -1 =9 here
Second : Question he is looking for do you know SET IDENTITY_INSERT
you have to SET IDENTITY_INSERT off for second table.
For the 2nd Problem, It can Be achieved By Turning ON The IDENTITY_INSERT for the Destination Table. Like this
CREATE TABLE dbo.TableA
(
Id INT IDENTITY(1,1),
Val VARCHAR(50)
)
CREATE TABLE dbo.TableB
(
Id INT IDENTITY(1,1),
Val VARCHAR(50)
)
INSERT INTO TableA(Val)
VALUES('ABC'),('HIJ'),('XYZ')
SET IDENTITY_INSERT TableB on
INSERT INTO TableB(Id,Val)
SELECT Id,Val FROM TableA
I have SQL statement which takes really a lot of time to execute and I really had to improve it somehow.
select * from table where ID=1 and GROUP in
(select group from groupteam where
department= 'marketing' )
My question is if I should create index on columns ID and GROUP would it help?
Or if not should I create index on second table on column DEPARTMENT?
Or I should create two indexes for both tables?
First table has 249003.
Second table has in total 900 rows while query in that table returns only 2 rows.
That is why I am surprised that response is so slow.
Thank you
You can also use EXISTS, depending on your database like so:
select * from table t
where id = 1
and exists (
select 1 from groupteam
where department = 'marketing'
and group = t.group
)
Create a composite index on individual indexes on groupteam's department and group
Create a composite index or individual indexes on table's id and group
Do an explain/analyze depending on your database to review how indexes are being used by your database engine.
Try a join instead:
select * from table t
JOIN groupteam gt
ON d.group = gt.group
where ID=1 AND gt.department= 'marketing'
Index on table group and id column and table groupteam group column would help too.
I have a stored procedure that uses a temporary table to make some joins in a select clause. The select clause contains the value from the Id column of the temporary table like this:
CREATE TABLE #TempTable
(
Id INT PRIMARY KEY,
RootVal INT
)
The Select looks like this:
Select value1, value2, #TempTable.Id AS ValKey
From MainTable INNER JOIN #TempTable ON MainTable.RootVal = #TempTable.RootVal
The query takes over a minute to run in real life but if I remove the "#TempTable.Id" from the select list it runs in a second.
Does anyone know why there is such a huge cost to including a value from a #temp table compared to just using it in a join?
Most likely:
data type mismatch
eg nvarchar vs int
lack of index on MainTable.RootVal
Why have Id as PK and then JOIN on another column?