I am using Liquibase for managing SQL Server scripts (create, update, delete, alters etc.).
My requirement was to create a backup table (say old_table_a) before I could drop two columns (column_1, column_2) from the original table (table_a).
The new backup table does not need a primary key, so it will just have two columns as shown below
old_table_a
column_1 (from original table_a)
column_2 (from original table_a)
If I just write INSERT query as shown below, without having a CREATE TABLE old_table_a
INSERT INTO old_table_a (column_1, column_2)
SELECT column_1, column_2
FROM table_a
I had read this somewhere on some blog, but cannot find this.
Please provide some information if this is possible.
Otherwise I know that the usual way to do this is to create the new backup table and then populate the new table with values from the original.
This can be done with SELECT * INTO:
SELECT * INTO [NEWTABLE] FROM [OLDTABLE]
INSERT tableName1 (ColumName)
(select (ColumName ) from TableName2)
Related
I have two tables with the same field names and a stored procedure that updates table B with Table A's data by doing a delete from current table and insert into current table from another table that has update values in it:
delete from ac.Table1
insert into ac.Table1
select *
from dbo.OriginalTable
where dtcreate <getdate()-1
I had to recreate Table1 through GIS software which adds GlobalIDs and an Object ID field. The original order had Object ID at the end and the new table has it at the front. Will this impact executing the SQL statement above?
Yes it will. The order of the columns should match for each value to go in desired column
You can try
Insert into ac.Table1 (column1....columnN)
I am using SQL Server 2012. I have same table on both server with 15 columns.first table has less records than second. I want to copy remaining records from second table to first. Both tables are on different SQL server. So I have created linked server. I was thinking about IF EXISTS. But i want to copy more records. I want to create script for this task. and I will use this frequently using task scheduler.(Note: I don't want to use Replication)
You Can Use Except Operator
For Example
Drop table #aa
Create table #aa (Id Int)
Insert into #aa
Select 1
Drop table #bb
Create table #bb (Id Int)
Insert into #bb
Select 1
Union all
Select 2
Insert into #aa
Select * from #bb
Except
Select * from #aa
I have situation where I need to change the order of the columns/adding new columns for existing Table in SQL Server 2008.
Existing column
MemberName
MemberAddress
Member_ID(pk)
and I want this order
Member_ID(pk)
MemberName
MemberAddress
I got the answer for the same ,
Go on SQL Server → Tools → Options → Designers → Table and Database Designers and unselect Prevent saving changes that require table re-creation
2- Open table design view and that scroll your column up and down and save your changes.
It is not possible with ALTER statement. If you wish to have the columns in a specific order, you will have to create a newtable, use INSERT INTO newtable (col-x,col-a,col-b) SELECT col-x,col-a,col-b FROM oldtable to transfer the data from the oldtable to the newtable, delete the oldtable and rename the newtable to the oldtable name.
This is not necessarily recommended because it does not matter which order the columns are in the database table. When you use a SELECT statement, you can name the columns and have them returned to you in the order that you desire.
If your table doesn't have any records you can just drop then create your table.
If it has records you can do it using your SQL Server Management Studio.
Just click your table > right click > click Design then you can now arrange the order of the columns by dragging the fields on the order that you want then click save.
Best Regards
I tried this and dont see any way of doing it.
here is my approach for it.
Right click on table and Script table for Create and have this on
one of the SQL Query window,
EXEC sp_rename 'Employee', 'Employee1' -- Original table name is Employee
Execute the Employee create script, make sure you arrange the columns in the way you need.
INSERT INTO TABLE2 SELECT * FROM TABLE1.
-- Insert into Employee select Name, Company from Employee1
DROP table Employee1.
Relying on column order is generally a bad idea in SQL. SQL is based on Relational theory where order is never guaranteed - by design. You should treat all your columns and rows as having no order and then change your queries to provide the correct results:
For Columns:
Try not to use SELECT *, but instead specify the order of columns in the select list as in: SELECT Member_ID, MemberName, MemberAddress from TableName. This will guarantee order and will ease maintenance if columns get added.
For Rows:
Row order in your result set is only guaranteed if you specify the ORDER BY clause.
If no ORDER BY clause is specified the result set may differ as the Query Plan might differ or the database pages might have changed.
Hope this helps...
This can be an issue when using Source Control and automated deployments to a shared development environment. Where I work we have a very large sample DB on our development tier to work with (a subset of our production data).
Recently I did some work to remove one column from a table and then add some extra ones on the end. I then had to undo my column removal so I re-added it on the end which means the table and all references are correct in the environment but the Source Control automated deployment will no longer work because it complains about the table definition changing.
The real problem here is that the table + indexes are ~120GB and the environment only has ~60GB free so I'll need to either:
a) Rename the existing columns which are in the wrong order, add new columns in the right order, update the data then drop the old columns
OR
b) Rename the table, create a new table with the correct order, insert to the new table from the old and delete from the old as I go along
The SSMS/TFS Schema compare option of using a temp table won't work because there isn't enough room on disc to do it.
I'm not trying to say this is the best way to go about things or that column order really matters, just that I have a scenario where it is an issue and I'm sharing the options I've thought of to fix the issue
SQL query to change the id column into first:
ALTER TABLE `student` CHANGE `id` `id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT FIRST;
or by using:
ALTER TABLE `student` CHANGE `id` `id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT AFTER 'column_name'
I need to merge data from 2 tables into a third (all having the same schema) and generate a mapping of old identity values to new ones. The obvious approach is to loop through the source tables using a cursor, inserting the old and new identity values along the way. Is there a better (possibly set-oriented) way to do this?
UPDATE: One additional bit of info: the destination table already has data.
Create your mapping table with an IDENTITY column for the new ID. Insert from your source tables into this table, creating your mapping.
SET IDENTITY_INSERT ON for your target table.
Insert into the target table from your source tables joined to the mapping table, then SET IDENTITY_INSERT OFF.
I created a mapping table based on the OUTPUT clause of the MERGE statement. No IDENTITY_INSERT required.
In the example below, there is RecordImportQueue and RecordDataImportQueue, and RecordDataImportQueue.RecordID is a FK to RecordImportQueue.RecordID. The data in these staging tables needs to go to Record and RecordData, and FK must be preserved.
RecordImportQueue to Record is done using a MERGE statement, producing a mapping table from its OUTPUT, and RecordDataImportQueue goes to RecordData using an INSERT from a SELECT of the source table joined to the mapping table.
DECLARE #MappingTable table ([NewRecordID] [bigint],[OldRecordID] [bigint])
MERGE [dbo].[Record] AS target
USING (SELECT [InstanceID]
,RecordID AS RecordID_Original
,[Status]
FROM [RecordImportQueue]
) AS source
ON (target.RecordID = NULL) -- can never match as RecordID is IDENTITY NOT NULL.
WHEN NOT MATCHED THEN
INSERT ([InstanceID],[Status])
VALUES (source.[InstanceID],source.[Status])
OUTPUT inserted.RecordID, source.RecordID_Original INTO #MappingTable;
After that, you can insert the records in a referencing table as folows:
INSERT INTO [dbo].[RecordData]
([InstanceID]
,[RecordID]
,[Status])
SELECT [InstanceID]
,mt.NewRecordID -- the new RecordID from the mappingtable
,[Status]
FROM [dbo].[RecordDataImportQueue] AS rdiq
JOIN #MappingTable AS mt
ON rdiq.RecordID = mt.OldRecordID
Although long after the original post, I hope this can help other people, and I'm curious for any feedback.
I think I would temporarily add an extra column to the new table to hold the old ID. Once your inserts are complete, you can extract the mapping into another table and drop the column.
I am working with SQL Server (I am a SQL Server noob) and trying to alter a table. I want to CREATE TABLE LIKE to safely store data while I drop keys and constraints and all the other rigamorole that SQL Server seems to require when altering on the original table but I have not been able to find a match to that command...
you want to recreate the same structure?
how about this
SELECT *
into test
FROM myRealTable
where 0=1
no data will be inserted into the new table
You can do
SELECT * INTO #MyTable_tmp FROM MyTable
Then modify your MyTable, and copy your data back in. Other approaches I've seen is to create a new table call it Mytable_Tmp (Not a temp table), which will be your new table.
Then copy your data doing any migrations you need. Then you will drop the original table and do a rename on Mytable.
Or you can get one of the many excellant tools that compare databases and generate difference scripts or VSTS DB Edition (Comes with developer) and you can do a diff script from a project file to a DB.
Edit
When you run SELECT * INTO #MyTable FROM MyTable, SQL Server creates a new temporary table called #MyTable that matches each column and data type from your select clause. In this case we are selecting * so it will match MyTable. This only creates the columns it doesn't copy defaults, constraints indexes or anything else.