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SQL -Create table if not exists, and insert value

I check my SQL database to see if a column exists if not create, but I wanted to insert a string in that column, but only if the column didn´t exist.
Otherwise I handle that information in my C# code.
So far I have this code :
string query = "IF NOT EXISTS (SELECT * FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = 'tabela' AND COLUMN_NAME = 'coluna') ALTER TABLE tabela ADD coluna varchar(50)" ;
SqlCommand command = new SqlCommand(query, con);
command.ExecuteNonQuery();
How should I do ?

Change your query to execute a block after the IF (psuedocode):
IF NOT EXISTS(...)
BEGIN
ALTER TABLE MyTable ...;
INSERT INTO MyTable ...;
END
Be sure to put semicolons at the end of the ALTER and INSERT commands, since you are sending these in a single command from an application, so SQL Server will see them as being all on one line.

You can write a trigger for each SELECT from the database object. In that you can first check if the column exists, and then you can do the needful. This you can achieve entirely by using SQL triggres (or even stored procedures
), C# has nothing to do with it :)
For more details on triggers, you can check this out

Take results of stored procedure and use in SQL query in my code behind

Due to some bad database design I've had to go through a bunch of steps to filter the results I'm looking for using a Stored Procedure and Table-valued Function. Now that I have the SP working properly and returning the records I want, I need to take those matches and work them back into the main sql query in my code behind.
So, I've got my stored procedure called usp_County which returns multiple records, then I have my normal query in code behind like this:
Select * From MyTable Where Name = #Name AND Address = #Address and so on.
Is there some (hopefully simple) way to work in my results from the stored procedure? Something along the lines of this maybe?
Select * From MyTable Where (dbo.usp_County(#county) AND Name = #Name AND Address = #Address and so on.
The results I'm trying to find are all in the same table that the SP is running against, just using the SP and this query to further filter.
For example, I want to search/query based on:
Name1 Address1 County(this is already populated by records through the SP)
Edit
My attempt at creating temp table:
CREATE TABLE #spResults (id int, Counties varchar(max))
INSERT INTO #spResults (id, Counties)
EXEC usp_County '#county'
GO

You can return sproc data into a temp table (sproc output data types must match table definition), then join to the temp table for the extra data & to apply your filter.
CREATE TABLE #spResults
(col1, col2, col3..)
INSERT INTO #spResults
EXEC sprocName(#Param)
SELECT * FROM MyTable JOIN #spResults ON <Cond>

Procedure returning a list of identity [duplicate]

I am inserting records through a query similar to this one:
insert into tbl_xyz select field1 from tbl_abc
Now I would like to retreive the newly generated IDENTITY Values of the inserted records. How do I do this with minimum amount of locking and maximum reliability?

You can get this information using the OUTPUT clause.
You can output your information to a temp target table or view.
Here's an example:
DECLARE #InsertedIDs TABLE (ID bigint)
INSERT into DestTable (col1, col2, col3, col4)
OUTPUT INSERTED.ID INTO #InsertedIDs
SELECT col1, col2, col3, col4 FROM SourceTable
You can then query the table InsertedIDs for your inserted IDs.

##IDENTITY will return you the last inserted IDENTITY value, so you have two possible problems
Beware of triggers executed when inserting into table_xyz as this may change the value of ##IDENTITY.
Does tbl_abc have more than one row. If so then ##IDENTITY will only return the identity value of the last row
Issue 1 can be resolved by using SCOPE__IDENTITY() instead of ##IDENTITY
Issue 2 is harder to resolve. Does field1 in tbl_abc define a unique record within tbl_xyz, if so you could reselect the data from table_xyz with the identity column. There are other solutions using CURSORS but these will be slow.

SELECT ##IDENTITY
This is how I've done it before. Not sure if this will meet the latter half of your post though.
EDIT
Found this link too, but not sure if it is the same...
How to insert multiple records and get the identity value?

As far as I know, you can't really do this with straight SQL in the same script. But you could create an INSERT trigger. Now, I hate triggers, but it's one way of doing it.
Depending on what you are trying to do, you might want to insert the rows into a temp table or table variable first, and deal with the result set that way. Hopefully, there is a unique column that you can link to.
You could also lock the table, get the max key, insert your rows, and then get your max key again and do a range.
Trigger:
--Use the Inserted table. This conaints all of the inserted rows.
SELECT * FROM Inserted
Temp Table:
insert field1, unique_col into #temp from tbl_abc
insert into tbl_xyz (field1, unique_col) select field1, unique_col from tbl_abc
--This could be an update, or a cursor, or whatever you want to do
SELECT * FROM tbl_xyz WHERE EXISTS (SELECT top 1 unique_col FROM #temp WHERE unique_col = tbl_xyz.unique_col)
Key Range:
Declare #minkey as int, #maxkey as int
BEGIN TRANS --You have to lock the table for this to work
--key is the name of your identity column
SELECT #minkey = MAX(key) FROM tbl_xyz
insert into tbl_xyz select field1 from tbl_abc
SELECT #maxkey = MAX(key) FROM tbl_xyz
COMMIT Trans
SELECT * FROM tbl_xyz WHERE key BETWEEN #minkey and #maxkey

Possible to insert with a Table Parameter, and also retrieve identity values?

I'm trying to insert records using a high performance table parameter method ( http://www.altdevblogaday.com/2012/05/16/sql-server-high-performance-inserts/ ), and I'm curious if it's possible to retrieve back the identity values for each record I insert.
At the moment, the answer appears to be no - I insert the data, then retrieve back the identity values, and they don't match. Specifically, they don't match about 75% of the time, and they don't match in unpredictable ways. Here's some code that replicates this issue:
// Create a datatable with 100k rows
DataTable dt = new DataTable();
dt.Columns.Add(new DataColumn("item_id", typeof(int)));
dt.Columns.Add(new DataColumn("comment", typeof(string)));
for (int i = 0; i < 100000; i++) {
dt.Rows.Add(new object[] { 0, i.ToString() });
}
// Insert these records and retrieve back the identity
using (SqlConnection conn = new SqlConnection("Data Source=localhost;Initial Catalog=testdb;Integrated Security=True")) {
conn.Open();
using (SqlCommand cmd = new SqlCommand("proc_bulk_insert_test", conn)) {
cmd.CommandType = CommandType.StoredProcedure;
// Adding a "structured" parameter allows you to insert tons of data with low overhead
SqlParameter param = new SqlParameter("#mytable", SqlDbType.Structured);
param.Value = dt;
cmd.Parameters.Add(param);
SqlDataReader dr = cmd.ExecuteReader();
// Set all the records' identity values
int i = 0;
while (dr.Read()) {
dt.Rows[i].ItemArray = new object[] { dr.GetInt32(0), dt.Rows[i].ItemArray[1] };
i++;
}
dr.Close();
}
// Do all the records' ID numbers match what I received back from the database?
using (SqlCommand cmd = new SqlCommand("SELECT * FROM bulk_insert_test WHERE item_id >= #base_identity ORDER BY item_id ASC", conn)) {
cmd.Parameters.AddWithValue("#base_identity", (int)dt.Rows[0].ItemArray[0]);
SqlDataReader dr = cmd.ExecuteReader();
DataTable dtresult = new DataTable();
dtresult.Load(dr);
}
}
The database is defined using this SQL server script:
CREATE TABLE bulk_insert_test (
item_id int IDENTITY (1, 1) NOT NULL PRIMARY KEY,
comment varchar(20)
)
GO
CREATE TYPE bulk_insert_table_type AS TABLE ( item_id int, comment varchar(20) )
GO
CREATE PROCEDURE proc_bulk_insert_test
#mytable bulk_insert_table_type READONLY
AS
DECLARE #TableOfIdentities TABLE (IdentValue INT)
INSERT INTO bulk_insert_test (comment)
OUTPUT Inserted.item_id INTO #TableOfIdentities(IdentValue)
SELECT comment FROM #mytable
SELECT * FROM #TableOfIdentities
Here's the problem: the values returned from proc_bulk_insert_test are not in the same order as the original records were inserted. Therefore, I can't programmatically assign each record the item_id value I received back from the OUTPUT statement.
It seems like the only valid solution is to SELECT back the entire list of records I just inserted, but frankly I'd prefer any solution that would reduce the amount of data piped across my SQL Server's network card. Does anyone have better solutions for large inserts while still retrieving identity values?
EDIT: Let me try clarifying the question a bit more. The problem is that I would like my C# program to learn what identity values SQL Server assigned to the data that I just inserted. The order isn't essential; but I would like to be able to take an arbitrary set of records within C#, insert them using the fast table parameter method, and then assign their auto-generated ID numbers in C# without having to requery the entire table back into memory.
Given that this is an artificial test set, I attempted to condense it into as small of a readable bit of code as possible. Let me describe what methods I have used to resolve this issue:
In my original code, in the application this example came from, I would insert about 15 million rows using 15 million individual insert statements, retrieving back the identity value after each insert. This worked but was slow.
I revised the code using high performance table parameters for insertion. I would then dispose of all of the objects in C#, and read back from the database the entire objects. However, the original records had dozens of columns with lots of varchar and decimal values, so this method was very network traffic intensive, although it was fast and it worked.
I now began research to figure out whether it was possible to use the table parameter insert, while asking SQL Server to just report back the identity values. I tried scope_identity() and OUTPUT but haven't been successful so far on either.
Basically, this problem would be solved if SQL Server would always insert the records in exactly the order I provided them. Is it possible to make SQL server insert records in exactly the order they are provided in a table value parameter insert?
EDIT2: This approach seems very similar to what Cade Roux cites below:
http://www.sqlteam.com/article/using-the-output-clause-to-capture-identity-values-on-multi-row-inserts
However, in the article, the author uses a magic unique value, "ProductNumber", to connect the inserted information from the "output" value to the original table value parameter. I'm trying to figure out how to do this if my table doesn't have a magic unique value.

Your TVP is an unordered set, just like a regular table. It only has order when you specify as such. Not only do you not have any way to indicate actual order here, you're also just doing a SELECT * at the end with no ORDER BY. What order do you expect here? You've told SQL Server, effectively, that you don't care. That said, I implemented your code and had no problems getting the rows back in the right order. I modified the procedure slightly so that you can actually tell which identity value belongs to which comment:
DECLARE #TableOfIdentities TABLE (IdentValue INT, comment varchar(20))
INSERT INTO bulk_insert_test (comment)
OUTPUT Inserted.item_id, Inserted.comment
INTO #TableOfIdentities(IdentValue, comment)
SELECT comment FROM #mytable
SELECT * FROM #TableOfIdentities
Then I called it using this code (we don't need all the C# for this):
DECLARE #t bulk_insert_table_type;
INSERT #t VALUES(5,'foo'),(2,'bar'),(3,'zzz');
SELECT * FROM #t;
EXEC dbo.proc_bulk_insert_test #t;
Results:
1 foo
2 bar
3 zzz
If you want to make sure the output is in the order of identity assignment (which isn't necessarily the same "order" that your unordered TVP has), you can add ORDER BY item_id to the last select in your procedure.
If you want to insert into the destination table so that your identity values are in an order that is important to you, then you have a couple of options:
add a column to your TVP and insert the order into that column, then use a cursor to iterate over the rows in that order, and insert one at a time. Still more efficient than calling the entire procedure for each row, IMHO.
add a column to your TVP that indicates order, and use an ORDER BY on the insert. This isn't guaranteed, but is relatively reliable, particularly if you eliminate parallelism issues using MAXDOP 1.
In any case, you seem to be placing a lot of relevance on ORDER. What does your order actually mean? If you want to place some meaning on order, you shouldn't be doing so using an IDENTITY column.

You specify no ORDER BY on this: SELECT * FROM #TableOfIdentities so there's no guarantee of order. If you want them in the same order they were sent, do an INNER JOIN in that to the data that was inserted with an ORDER BY which matches the order the rows were sent in.

How to delete a record?

I have records in table1, if the records exist, it must copy into table2. I want to delete those records in a table1 once all the records are copied into another table2. Im still a beginner in database and with some researches, i found some tutorials on d internet how to connect with database, and the codes easy to understand so i came out with this program.This codes only do the copy part and i'm still lack of the delete part. Can help me figure out how to do the delete part? i found 2 reference in msdn, but i'm not sure and not understand on the codes given.
try
{
//create connection
System.Data.SqlClient.SqlConnection sqlConnection1 =
new System.Data.SqlClient.SqlConnection("Data Source=.dbname;Integrated Security=True;User Instance=True");
//command queries
System.Data.SqlClient.SqlCommand cmd = new System.Data.SqlClient.SqlCommand();
cmd.CommandType = System.Data.CommandType.Text;
cmd.CommandText = "INSERT INTO tblSend (ip, msg, date) SELECT ip, msg, date FROM tblOutbox";
cmd.Connection = sqlConnection1;
sqlConnection1.Open(); //open con
cmd.ExecuteNonQuery(); //execute query
sqlConnection1.Close(); //close con
}
catch (System.Exception excep)
{
MessageBox.Show(excep.Message);
}
If i replace the query into this: //cmd.CommandText = "DELETE tblSend WHERE id = 5";
its only delete one rows. But what if many records involved? Do i need to consider the EOF things? DO i need to use DataGridView? Becoz the code i did didn't use DataGridView at all. i dont want the records to be displayed, i just want it to running behind.

No you do not need a worry about EOF or using a DataGridView. Just as you can use an ExecuteNonQuery method to insert multiple rows you can also do the same when using DELETE.
Data manipulation statements such as INSERT, UPDATE and DELETE do not generate a result set and hence you would normally use ExecuteNonQuery to run them. All the data manipulation runs in the database server engine.

If I understand correctly you need all data from table1 in table2 and then delete table1.
Options
1) It you need it once you could rename table1 to table2 and recreate table1
-- move the records to table 2, ok I assume it does not exist;)
RENAME TABLE table1 TO table2;
-- Create new table1 with same structure as table 2
CREATE TABLE table1 AS SELECT * FROM table2 WHERE 1=2;
2) Do a separate copy and delete assuming you have something like a primary key
-- copy the records
INSERT table2(field1, field2, ...) SELECT field1, field2, ... FROM table1;
-- and delete them
DELETE FROM table1;
3) Do it using C# but as this seems a database problem to me I would not go that far in pulling all the records to the client and then throwing them back.

DELETE FROM tblSend WHERE id = 5;
This will delete all rows that match the WHERE condition.
I am not sure I understand the relevance of the DataGridView. If it is databound, it will automatically remove the records as well. You only need to issue the delete query once and the rest should happen automatically, assuming you have the databinding correct.

What do you mean by "if they exist"? Compared to what?
To delete multiple records from table 1, you have to make a loop which goes through your table and compare.
Pseudo code:
forach (whatever as whut)
row = select whatever from table1.
if (whut == row)
copy row from table 1 to table 2;
Delete from table 1 where whut.id == row.id;

DELETE FROM tblSend WHERE id = 5;
This is the one solution for deletion a record.
If you want to set the identity key to 0 again, use this code
DBCC CHECKIDENT('tblSend', RESEED, 0);
Then press F5,