This question already has an answer here:
Finding updated records in SSIS -- to hash or not to hash?
(1 answer)
Closed 5 years ago.
I've the following workflow in SSIS 14:
Each source have more than million records and I need to execute this workflow everydays at week.
My question is: How can I say to SSIS that I only want to extract only the records that not exists in Table Destination? Like a
INSERT INTO TABLEA
SELET * FROM TABLEB
EXCEPT SELECT * FROM TABLEA
Many thanks!
You can use the Lookup transformation to find out if something exists already.
Related
This question already has answers here:
How can I get column names from a table in SQL Server?
(22 answers)
Closed 6 months ago.
I have a table name as 'tblOrder', having three columns. I would like to print the column names.
I want a script that should return a result as:
OrderId Name OrderTrackingNo
SELECT * FROM sys.columns WHERE object_id = OBJECT_ID('tblOrder')
Try this
This question already has answers here:
IN vs OR in the SQL WHERE clause
(8 answers)
Closed 5 years ago.
I would like to know from below queries, which one would give better performance and how?
select * from TableA where (Name = 'ABC' or Name = 'DEF' or Name = 'GHI')
or
select * from TableA where Name in ('ABC','DEF','GHI')
Internally both IN and OR operators perform the same action. More importantly you need to see if you have proper index on the Name column.You can have a non-clustered index on the Name column and have one clustered index on this table.
This question already has an answer here:
Does wrapping nullable columns in ISNULL cause table scans?
(1 answer)
Closed 5 years ago.
Is any diff in below query in term of performance??
select COLUMN1,column2 from table
where COLUMN1 is not null
and COLUMN1 <>'';
select COLUMN1,column2 from table
where isnull(Column1,'')<>'';
You can obtain an execution plan for your query to determine the cost of that operation.
How to do it and the output format really depends on each database product.
In the case of SQL server it may look like:
My intuition tells me that operation in particular should not be expensive. What would rather be expensive is to query a column that is not indexed.
This question already has answers here:
INSERT INTO vs SELECT INTO
(11 answers)
Closed 8 years ago.
There are two way to copy data from one table to another.
1. First create a new table then using "
INSERT INTO TABLE2_NAME
SELECT * FROM TABEL1_NAME"
OR
2. SELECT * INTO TABLE2_NAME FROM TABLE1_NAME
I am using SQL Server 2012.
They are different inasmuch that the first one needs to have the table already created, the second one will create the table too.
I would pretty much bet that the execute plan for the read on TABLE1_NAME will be the same ergo the second is probably a few millisecs slower as it has to create the table.
Now the next thing to take into account is where the table is being created. In the first on you may have placed the table on fast storage while in the second the it will go to to the default primary storage which may or may not be optimised.
If all things are equal - then it's likely a micro optimisation that isn't worth considering.
The INSERT INTO TABLE2_NAME SELECT * FROM TABEL1_NAME creates TABLE2_NAME and inserts the values of TABEL1_NAME in them. It is more efficient but if the table is already created that statement would give an error.
The SELECT * INTO TABLE2_NAME FROM TABLE1_NAME only inserts the values of TABLE1_NAME in TABEL2_NAME.
This question already has answers here:
Closed 11 years ago.
Possible Duplicate:
Why (and how) to split column using master..spt_values?
I have seen something like:
Selet ... from master..spt_values where type='P'
What does this mean?
That is the syntax for specifying a databasename, schema, and table name. You can use this syntax to specify a database different from the database you are currently connected to. In your example, master is the database name, the schema name is unspecified (so it becomes the default dbo schema) and spt_values is the table name.
For clarity, the above could also be: Select ... from master.dbo.spt_values