Dynamically update queries as new database comes into existence - sql

Platform: SQL Server 2008
Language: TSQL
I have a number of queries that currently take the general form of (for simplicity sake)
-- Sample begin results
SELECT * from DB01.dbo.table UNION ALL
SELECT * from DB02.dbo.table UNION ALL --many other databases follow with same syntax
How can I modify these queries such that, when a new database comes into existence (named, say DB39C), I ensure that my queries already includes those new records?
--Sample end results
SELECT * from DB01.dbo.table UNION ALL
SELECT * from DB02.dbo.table UNION ALL
SELECT * from DB39C.dbo.table -- this was created as soon as a new database came into existence
I am looking to make sure programmatically, that this happens without my awareness as new databases are added quite regularly and I need the queries I rely on to keep pace.

You might want to have a look at using something like
SELECT name AS DATABASENAME
FROM master.dbo.sysdatabases
and creating dynamic queries
sys.databases (Transact-SQL)

Related

Drop tables using table names from a SELECT statement, in SQL (Impala)?

How do I drop a few tables (e.g. 1 - 3) using the output of a SELECT statement for the table names? This is probably standard SQL, but specifically I'm using Apache Impala SQL accessed via Apache Zeppelin.
So I have a table called tables_to_drop with a single column called "table_name". This will have one to a few entries in it, each with the name of another temporary table that was generated as the result of other processes. As part of my cleanup I need to drop these temporary tables whose names are listed in the "tables_to_drop" table.
Conceptually I was thinking of an SQL command like:
DROP TABLE (SELECT table_name FROM tables_to_drop);
or:
WITH subquery1 AS (SELECT table_name FROM tables_to_drop) DROP TABLE * FROM subquery1;
Neither of these work (syntax errors). Any ideas please?
even in standard sql this is not possible to do it the way you showed.
in standard sql usually you can use dynamic sql which impala doesn't support.
however you can write an impala script and run it in impala shell but it's going to be complicated for such task, I would prepare the drop statement using select and run it manually if this is one-time thing:
select concat('DROP TABLE IF EXISTS ',table_name) dropstatements
from tables_to_drop

Query with multiple schemas - Dbeaver

I have 5 schemas under one db. 3 of them have exactly the same tables and fields.
I want to create queries that call those 3 schemas at once.
Im using DBeaver version 7.2.2
I already checked the box 'use global search' and it didn't help.
Maybe I need to do something in the sql editor itself?
for example, I want to call 'users' table and it will give me the data from all 3 tables.
I think to do that you will need to call all three schemas/tables individually. You can still return all results in one go, though.
For example:
SELECT * FROM schema1.users
UNION ALL
SELECT * FROM schema2.users
UNION ALL
SELECT * FROM schema3.users
;

Oracle system information query - Database instance level

I am writing a performance/system monitoring tool to augment load testing for my team's product and I am trying to store database system information with the results bundle but do not know how to write the query to capture this in Oracle (I'm a developer not a DBA).
I have this all working the way I want for SQL Server, but I need to do the same for Oracle. Below is a query I found online for this is SQL Server:
SELECT CONVERT(varchar(128),SERVERPROPERTY('ComputerNamePhysicalNetBIOS')) AS 'computerNamePhysicalNetBIOS',
CONVERT(varchar(128),SERVERPROPERTY('MachineName')) AS 'machineName',
CONVERT(varchar(128),SERVERPROPERTY('Edition')) AS 'edition',
CONVERT(varchar(128),SERVERPROPERTY('ProductLevel')) AS 'productLevel',
CONVERT(varchar(128),SERVERPROPERTY('ProductVersion')) AS 'productVersion',
CONVERT(varchar(128),SERVERPROPERTY('BuildClrVersion')) AS 'buildClrVersion',
CONVERT(INT,SERVERPROPERTY('ProcessID')) AS 'processID',
CONVERT(INT,SERVERPROPERTY('EngineEdition')) AS 'engineEdition',
CONVERT(INT,SERVERPROPERTY('HadrManagerStatus')) AS 'hadrManagerStatus',
CONVERT(INT,SERVERPROPERTY('IsHadrEnabled')) AS 'hadrEnabled',
CONVERT(INT,SERVERPROPERTY('IsAdvancedAnalyticsInstalled')) AS 'advancedAnalyticsInstalled',
CONVERT(INT,SERVERPROPERTY('IsClustered')) AS 'clustered',
CONVERT(INT,SERVERPROPERTY('IsPolybaseInstalled')) AS 'polybaseInstalled',
CONVERT(INT,SERVERPROPERTY('IsXTPSupported')) AS 'xtpSupported',
CONVERT(INT,SERVERPROPERTY('LCID')) AS 'lcid',
CONVERT(varchar(128),SERVERPROPERTY('ResourceVersion')) AS 'resourceVersion',
CONVERT(varchar(128),SERVERPROPERTY('ServerName')) AS 'serverName',
CONVERT(varchar(128),APP_NAME() )AS 'appName',
CONVERT(INT,DB_ID()) AS 'dbId',
CONVERT(varchar(128),DB_NAME()) AS 'dbName'
I don't really expect a one-to-one column match between the above query and Oracle's version, but in general, how can I get very similar information from Oracle?
I don't really expect a one-to-one column match between the above
query and Oracle's version, but in general, how can I get very similar
information from Oracle?
Most of that stuff, if it exists at all in the Oracle database, will be accessible through V$ views in the Oracle database. To get you started, here are some that are going to be most relevant to answering your question:
select * from v$instance;
select * from v$version;
select * from v$sql_feature;
select * from v$license;
select * from v$option;
If you want to get a complete list of V$ views to look around better,
select * from dict where table_name like 'V$%';
Some of those things are specific to MSSQL and have no meaning in Oracle. But you can get many of them with sys_context() using the userenv namespace.
For instance, to get the database name:
select sys_context('userenv', 'DB_NAME') as db_name
from dual;

sql server shortcut for select statement writing

Many times a day I have to write similar queries to get single record:
select t.*
from some_table t
where t.Id = 123456
maybe there is some shortcuts for retrieving single record? Like entering id, table and SQL server generates rest code automatically
In Sql Server Go to
Tools-> Options-> Environments->Keyboard
You will get shortcuts, there you can define your own as well as get the standards.
you can set a short cut for a fully executable query like
select * from table where id =20
but not like below
select * from

Query across multiple databases on same server

I am looking for a way of dealing with the following situation:
We have a database server with multiple databases on it (all have the same schema, different data).
We are looking for a way to query across all the databases (and for it to be easy to configure, as more databases may be added at any time). This data access must be realtime.
Say, as an example, you have an application that inserts orders - each application has its own DB etc. What we are then looking for is an efficient way for a single application to then access the order information in all the other databases in order to query it and subsequently action it.
My searches to date have not revealed very much, however I think I may just be missing the appropriate keywords in order to find the correct info...
You must specify the database name before any database object.
Single database:
SELECT * FROM [dbo].[myTable]
Multiple dabases:
SELECT * FROM [DB01].[dbo].[myTable]
UNION ALL
SELECT * FROM [DB02].[dbo].[myTable]
UNION ALL
SELECT * FROM [DB03].[dbo].[myTable]
It's not going to be the cleanest solution ever, but you could define a view on a "Master database" (if your individual databases are not going to stay constant) that includes the data from the individual databases, and allows you to execute queries on a single source.
For example...
CREATE VIEW vCombinedRecords AS
SELECT * FROM DB1.dbo.MyTable
UNION ALL
SELECT * FROM DB2.dbo.MyTable
Which allows you to do...
SELECT * FROM vCombinedRecords WHERE....
When your databases change, you just update the view definition to include the new tables.
You can build the union dynamically:
select name from sys.databases
and then check if the database has the table:
select name from [dbname_from_above].sys.tables where name = 'YourTable'
That gives you all databases for the union. You can build the query client side or in dynamic SQL.
Note - My answer below received a couple down votes, but only one comment giving any reason why it might be down-voted. The comment was that this answer is very similar to the accepted answer, but even less performant. I disagree with this opinion and I reproduce my response here - in the actual answer - so that anyone else reading my answer might have a better chance at seeing why this is not the same as the accepted answer at all, and in fact better addresses the original question.
My response to the suggestion this is similar to the accepted answer:
on the contrary - the original question notes that new databases are added regularly. The accepted solution will require maintenance each time a new database is added. The solution here will work regardless of whether any new databases are added (in line with the original question that states they all have the same schema). Further, the accepted answer requires you to duplicate the query once per database queried. If the query is complex, that gets ugly fast. The proposal here ensures a single source of truth for the logic being used in the query.
And the answer itself:
Shooting from the hip here.
use master;
go
create table #Temp (sourceDBName varchar(128), colA varchar(128), colB varchar(128));
exec sp_MSforeachDB ' USE [?];
insert into #Temp
SELECT DISTINCT
''?'',
tableA.colA,
tableB.colB
FROM tableA JOIN tableB on some_conditions
WHERE someCol LIKE ''%some_term%''
'
select sourceDBName, colA, colB from #Temp order by 1, 2, 3;
drop table #Temp;
This logic should allow you to apply a single query to all databases. To use it though, you will want to add logic to filter out system databases, or explicitly include only the databases you specify. To achieve that, you might like to put this logic into a stored procedure which then returns a result set, so in the end, your call to this logic is a select statement that returns a rowset you can join, filter, etc.
Check out https://www.mssqltips.com/sqlservertip/2855/sql-server-multi-database-query-with-registered-servers/
SELECT * FROM (
SELECT
##SERVERNAME as [ServerName],
##version [Version],
Format(##CONNECTIONS,'N0') [Conections],
Format(##CPU_BUSY ,'N0')[CPUBusy]
) SQLInfo
LEFT JOIN (
SELECT
##SERVERNAME AS [ServerName],
SERVERPROPERTY('ProductVersion') [Version Build],
SERVERPROPERTY ('Edition') AS [Edition],
SERVERPROPERTY('ProductLevel') AS [Service Pack],
CASE SERVERPROPERTY('IsIntegratedSecurityOnly')
WHEN 0 THEN 'SQL Server and Windows Authentication mode'
WHEN 1 THEN 'Windows Authentication mode'
END AS [Server Authentication],
CASE SERVERPROPERTY('IsClustered')
WHEN 0 THEN 'False'
WHEN 1 THEN 'True'
END AS [Is Clustered?],
SERVERPROPERTY('ComputerNamePhysicalNetBIOS') AS [Current Node Name],
SERVERPROPERTY('Collation') AS [ SQL Collation],
[cpu_count] AS [CPUs],
[physical_memory_kb]*0.00000095367432 AS [RAM (GB)]
FROM [sys].[dm_os_sys_info]
) SQLInfo2 on SQLInfo.[ServerName]=SQLInfo2.[ServerName]
LEFT JOIN (
SELECT
##SERVERNAME as [ServerName],
NodeName,
Status_Description,
is_Current_Owner
FROM [MASTER].[sys].[fn_virtualservernodes]()
)Clusterinfo on SQLInfo.[ServerName]=Clusterinfo.[ServerName]