Know identity before insert - sql

I want to copy rows from the table within the table itself. But before inserting I need to modify a varchar column appending the value of identity column to it.
My table structure is:
secID docID secName secType secBor
1 5 sec-1 G 9
2 5 sec-2 H 12
3 5 sec-3 G 12
4 7 sec-4 G 12
5 7 sec-5 H 9
If I want to copy data of say docID 5, currently this runs through a loop one row at a time.
I can write my query as
insert into tableA (docID, secName, secType, secBor)
select 8, secName, secType, secBor from tableA where docID = 5
But how can I set value of secName before hand so that it becomes sec-<value of secID column>?

Don't try to guess the value of identity column. In your case you could simply create a computed column secName AS CONCAT('sec-', secID). There is no further need to update that column.
DB Fiddle
It is also possible to create an AFTER INSERT trigger to update the column.

Since SQL Server does not have GENERATED ALWAYS AS ('Sec - ' + id) the only simple option I see is to use a trigger.

Adding to my comment something like:
insert into tableA (docID, secName, secType, secBor)
select
ROW_NUMBER() OVER (ORDER BY DocID),
'Sec -'+ ROW_NUMBER() OVER (ORDER BY DocID),
secType, secBor
from tableA
where docID = 5

In SQL Server 2012 and later, you can achieve this by using the new sequence object.
CREATE SEQUENCE TableAIdentitySeqeunce
START WITH 1
INCREMENT BY 1 ;
GO
create table TableA
(
secId int default (NEXT VALUE FOR TableAIdentitySeqeunce) not null primary key,
varcharCol nvarchar(50)
)
declare #nextId int;
select #nextId = NEXT VALUE FOR TableAIdentitySeqeunce
insert TableA (secId, varcharCol)
values (#nextId, N'Data #' + cast(#nextId as nvarchar(50)))

Related

ignoring last value if its the same as current value

I have an table where i would like to query the following:
The data comes in batches . This data is combined with an id.
This ID only gets send ones when the new batch comes in. After that the ID only changes when there is a new batch . In the mean time the value stays null
What i need to do is if new data comes in and it has the same id as the previous batch i have to continue the insert with null in the id field instead of pushing a new row with the same id value.
Beneath is a simplistic view of the table
ID Values
1 10
null 20
null 20
null 20
null 20
2 20
null 20
null 20
null 20
null 20
1 20
null 20
If you could help me point in a directions that would help me a lot.
Maybe to clearify the id value is a set of tags. So there are some definied tags(100 or more) and when a new batch comes the batch gets a tag with it. And if that tag is the same as the previous the null has to continue instead of inserting the same tag
You'll need to add an identity field (or a timestamp) in order to be able to query the latest ID.
ALTER TABLE MyTable ADD MyIdent INT IDENTITY(1, 1) NOT NULL
Then on your insert (if your Id value is NULL) you can call
INSERT INTO MyTable (Id, Values)
SELECT TOP 1 Id, #ValuesVariable
FROM MyTable
WHERE Id IS NOT NULL
ORDER BY MyIdent DESC
This below Sp may helps to inert data try this
IF OBJECT_ID('tempdb..#Temp')IS NOT NULL
DROP TABLE #Temp
CREATE TABLE #Temp (ID INT,[Values] INT)
CREATE PROCEDURE usp_Insert
(
#Id INT,
#Values INT
)
AS
BEGIN
IF NOT EXISTS (SELECT 1 FROM #Temp WHERE ID = #ID)
BEGIN
INSERT INTO #Temp(ID,[Values])
SELECT #Id,#Values
END
ELSE
INSERT INTO #Temp(ID,[Values])
SELECT NULL,#Values
END
EXEC usp_Insert 2,12
SELECT * FROM #Temp

Update sub-index when inserting in SQL

I have a table that simplified looks like this:
group index value
1 1 text 1
1 2 text 2
1 3 text 3
2 1 text 4
2 2 text 5
2 3 text 6
Group is an foreign key that is also used for grouping items in the table.
Index is an internal index for sorting the items within the group.
Text is just a value.
Then if I do an insert or running a stored procedure to do the insert
INSERT INTO Table VALUES (1, 2, 'new text')
I would like to update the index for the group 1 items so the table looks like this:
group index value
1 1 text 1
1 2 new text (inserted)
1 3 text 2 (index updated)
1 4 text 3 (index updated)
2 1 text 4
2 2 text 5
2 3 text 6
(Running on MS SQL-Server 2008)
This is a store procedure you can use. Takes 3 parameters, grp, idx, and value:
CREATE PROCEDURE ReIndex
#grp int,
#idx int,
#value nvarchar(30)
AS
IF NOT EXISTS(SELECT 1 FROM [tbl] WHERE grp = #grp and idx =#idx)
INSERT INTO tbl VALUES (#grp, #idx, #value)
else
update tbl
set idx = idx+1
where
grp =#grp and
idx >= #idx
INSERT INTO tbl VALUES (#grp, #idx, #value)
Usage:
exec reindex 1, 2, 'new text'
sqlfiddle: http://sqlfiddle.com/#!3/3323d/11
In this answer I'll assume the first column names are grp and idx, as group and index are reserved words in SQL.
You can use the next available idx value by using a MAX(idx)+1 formula, like this:
INSERT INTO t1(grp, idx, value)
SELECT 1, IFNULL(MAX(idx),0)+1, 'new text'
FROM t1
WHERE grp = 1;
But this way two records inserted at about the same time might get the same idx value. To avoid this you could lock your table while inserting the record. You can do that by wrapping the above statement with table lock/unlock statements:
LOCK TABLES t1;
...
UNLOCK TABLES;
However, this method cannot be used within procedures. There the solution involves creating a transaction, and a SELECT ... FOR UPDATE. Note that you need InnoDB Storage for this:
CREATE PROCEDURE ins_val(IN pgrp int, IN pvalue varchar(200))
BEGIN
DECLARE newidx INT;
START TRANSACTION;
SELECT IFNULL(MAX(idx),0)+1
INTO newidx
FROM t1
WHERE grp = pgrp;
FOR UPDATE;
INSERT INTO t1(grp, idx, value)
VALUES (pgrp, newidx, pvalue);
COMMIT;
END;
Note that if you later delete records, these will leave gaps in the idx numbering that will not be filled again by the above method. On the other hand, if the records with the highest idx value is deleted, the next inserted record will re-use that idx value.

How to generate AUTOMATIC Number in Teradata SQL

I want to generate AUTOMATIC Number to use TD SQL, for example as follows,
CREATE MULTISET TABLE TEST_TABLE
(
AUTO_NUMBER INT,
NAME VARCHAR(10)
)
PRIMARY INDEX (AUTO_NUMBER);
INSERT INTO TEST_TABLE
VALUES('TOM');
INSERT INTO TEST_TABLE
VALUES('JIM');
INSERT INTO TEST_TABLE
VALUES('JAN');
SELECT * FROM TEST_TABLE;
The result above will be ,
1 TOM
2 JIM
3 JAN
Create a column with the below syntax:
SEQ_NUM decimal(10,0) NOT NULL GENERATED ALWAYS AS IDENTITY
(START WITH 1
INCREMENT BY 1
MINVALUE 1
MAXVALUE 2147483647
NO CYCLE)
Usually there is a column in the table which is unique.
You can use below technique to add a column in your result set if you dont want to add extra column to your table.
select RANK() OVER ( ORDER BY ),T.* SEQ from TABLE T;
It will give you output like:
1 a xx yy
2 b xx yy
3 c xx yy

SQL Server 2012 Sequence Object

Here is my sample table, the primary key is a composite key of Akey+Bkey
Akey Bkey ItemSequence
---- ---- ------------
1 1 1
1 5 2
1 7 3
2 7 1
3 2 1
3 3 2
Akey is generated from a SQL 2012 Sequence object ASequence. In most cases I insert one row at a time and when necessary I call NEXT VALUE FOR ASequence. However I need to do an insert from a statement like:
SELECT DENSE_RANK() OVER ( ORDER BY Something) as AKey,
Bkey, Sequence
FROM TABLEB
The OVER clause of the NEXT VALUE does not work this way as I need to be able to insert records as a SET but only increment the Sequence once per DENSE_RANK set.
So we have the ALTER SEQUENCE command and with this I am able to set the sequence to what I want. The caveat to this is that it must be a constant and will not accept a variable. My workaround to this was:
DECLARE #startingID INT
DECLARE #sql VARCHAR(MAX)
DECLARE #newSeed INT
SET #startingID = NEXT VALUE FOR ASequence
INSERT TABLEA
SELECT DENSE_RANK() OVER ( ORDER BY Something) + #startingID as AKey,
Bkey, Sequence
FROM TABLEB
SELECT #newSeed = MAX(Akey) FROM TABLEA
SET #sql = ‘ALTER SEQUENCE ASEQUENCE RESTART WITH ‘ + cast(#newSeed+1 as varchar(10))
EXEC(#sql)
Seems terrible to have DML statements in Dynamic SQL like this. Is there a better way to do this?
This should do it:
INSERT TABLEA
SELECT NEXT VALUE FOR ASequence OVER(ORDER BY Something) as AKey,
Bkey, Seq
FROM TABLEB
Or, how about this:
CREATE TABLEA
(
GroupID INT,
AKey INT,
BKey INT,
ItemSequence INT,
CONSTRAINT PK_TABLEA PRIMARY KEY CLUSTERED
(
GroupID,
AKey,
BKey
)
)
DECLARE #GroupID INT
SET #GroupID = NEXT VALUE FOR ASequence
INSERT TABLEA
SELECT #GroupID, DENSE_RANK() OVER ( ORDER BY Something) as AKey,
Bkey, Sequence
FROM TABLEB
and if you need the value of AKey as it is in your example, you can do GroupID+AKey here.

How to increment a second primary key column in a table automatically when a new entry is added for the first primary key column

I am trying to find a way to increment a second primary key column in a table automatically when a new entry is added for the first primary key column. I suppose an example would be best here so here goes.
Suppose I have a table:
CREATE TABLE T
(
SecNum INT NOT NULL,
EntryID INT NOT NULL,
Value FLOAT,
) CONSTRAINT [PK_T] PRIMARY KEY CLUSTERED
(
[SecNum] ASC,
[EntryID] ASC
)
I would run the following statement:
INSERT INTO T (SecNum, Value) VALUES (0, 10)
My table should look like:
SECNUM | ENTRYID | VALUE
-------------------------
0 0 10
I would run the following statement:
INSERT INTO T (SecNum, Value) VALUES (0, 10)
My table should look like:
SECNUM | ENTRYID | VALUE
-------------------------
0 0 10
0 1 10
I would run the following statement:
INSERT INTO T (SecNum, Value) VALUES (1, 20)
My table should look like:
SECNUM | ENTRYID | VALUE
-------------------------
0 0 10
0 1 10
1 0 20
This is possible using an INSTEAD OF trigger:
CREATE TRIGGER TriggerName
ON T
INSTEAD OF INSERT
AS
-- THIS TOP BIT IS OPTIONAL, IT WILL ALLOW ENTRY ID TO BE OVERRIDDEN IF
-- IT IS SUPPLIED TO THE INSERT AND WILL NOT VIOLATE THE PRIMARY KEY
IF NOT EXISTS
( SELECT 1
FROM T
INNER JOIN inserted i
ON i.SecNum = T.secNum
AND i.EntryID = T.EntryID
UNION
SELECT 1
FROM inserted
WHERE EntryID IS NULL
)
BEGIN
INSERT T (SecNum, EntryID, Value)
SELECT SecNum, EntryID, Value
FROM inserted
END
ELSE
-- IF OVERRIDE ABILITY IS NOT REQUIRED JUST USE THE BELOW INSERT
BEGIN
INSERT T (SecNum, EntryID, Value)
SELECT i.SecNum, COALESCE(LastID, 0), i.Value
FROM inserted I
LEFT JOIN
( SELECT SecNum, MAX(T.EntryID) + 1 [LastID]
FROM T
GROUP BY SecNum
) T
ON T.SecNum = i.SecNum
END
Example here
HOWEVER this is not very elegant. It could be worth asking is it really necessary? Could you get away with using a surrogate primary key, and use ROW_NUMBER() to create Entry ID's on the fly?
How about something like this:
INSERT INTO T (SecNum, Value, EntryId)
SELECT 0, 10, count(*)
FROM T WHERE SecNum = 0
It is not the cleanest solution and will perform pretty poorly too. But it should get the job done.
This is how to do it without storing the value in the table (I'm not sure why you want to store it)
TABLE
DECLARE #T TABLE
(
SecNum INT NOT NULL,
EntryID INT,
Value FLOAT
)
DATA
INSERT INTO #T
( SecNum, Value )
VALUES ( 0, 10 )
INSERT INTO #T
( SecNum, Value )
VALUES ( 0, 10 )
INSERT INTO #T
( SecNum, Value )
VALUES ( 1, 20 )
QUERY
SELECT SecNum,
ROW_NUMBER() OVER ( PARTITION BY value ORDER BY Value ) - 1 AS EntryID,
Value
FROM #T
RESULT
SecNum EntryID Value
0 0 10
0 1 10
1 0 20
If the EntryID changes with SecNum AND Value use this query:
SELECT SecNum,
ROW_NUMBER() OVER ( PARTITION BY Value,SecNum ORDER BY Value, SecNum ) - 1 AS EntryID,
Value
FROM #t
RESULT 2
SecNum EntryID Value
0 0 10
0 1 10
1 0 10
1 0 20
Your problem can be solved by using an instead of insert trigger
create trigger Trigger1 on T INSTEAD OF INSERT
as
begin
insert into T(SecNum,EntryID,Value)
select SecNum,
(select count(*) from T where SecNum = i.SecNum) as EntryID,
value
from inserted i
end