When we are working with different versions of database, database professionals are comparing the objects between databases of SQL Server.
They must make sure about that all databases are in sync.

Using this T-SQL Script, you can compare two databases and find a list of unmatched objects like: Constraints, Tables, Views, Stored Procedure, Triggers.

Sample demonstration:
First, Create two sample databases:

CREATE DATABASE ABC
GO
CREATE DATABASE XYZ
GO

Create few sample tables in both the databases:

CREATE TABLE ABC.dbo.tbl_Test
(
	ID INT
	,MyDate DATE
)
GO

CREATE TABLE ABC.dbo.tbl_MyTest
(
	ID INT
	,Name VARCHAR(50)
)
GO

CREATE TABLE XYZ.dbo.tbl_Test
(
	ID INT
	,MyDate DATE
)
GO

CREATE TABLE XYZ.dbo.tbl_MyFinal
(
	ID INT
	,Name VARCHAR(50)
)
GO

T-SQL Script to compare objects between two databases:
According to your databases, You can change the name of @SourceDatabase and @DestinationDatabase.

DECLARE @SourceDatabase VARCHAR(50) 
DECLARE @DestinationDatabase VARCHAR(50) 
DECLARE @SQL VARCHAR(MAX) 
     
SELECT @SourceDatabase = 'ABC' 
SELECT @DestinationDatabase = 'XYZ'
     
SELECT @SQL = 
'
	SELECT 
		ISNULL(S.name,D.name) ObjectName
		,CASE  
			WHEN S.object_id IS NULL 
				THEN D.type_desc + '' is missing in the Source Database: '	+ @SourceDatabase + ''' 
			WHEN D.object_id IS NULL 
				THEN S.type_desc +  '' is missing in the Destination Database: ' + @DestinationDatabase + ''' 
		END ''Status'' 
	FROM 
	(
		SELECT * FROM ' + @SourceDatabase + '.SYS.objects  
		WHERE Type_desc not in (''INTERNAL_TABLE'',''SYSTEM_TABLE'',''SERVICE_QUEUE'')
	) AS S  
	FULL OUTER JOIN 
	(
		SELECT * FROM ' + @DestinationDatabase + '.SYS.objects  
		WHERE Type_desc not in (''INTERNAL_TABLE'',''SYSTEM_TABLE'',''SERVICE_QUEUE'')
	) AS D 
	ON S.name = D.name 
		AND S.type = D.type 
	ORDER BY isnull(S.type,D.type)
'  
EXEC (@Sql)

The Result:

ObjectName                         Status
------------------  -------------------------------------------------------
tbl_Test              NULL
tbl_MyFinal           USER_TABLE is missing in the Source Database: ABC
tbl_MyTest            USER_TABLE is missing in the Destination Database: XYZ

In this post, I am sharing a script for checking the Network and Connect related permission of SQL Server User.

When you installed the SQL Server, for network access you should enable the TCP/IP pipeline and other connect permission so that others can access the server.

Using below script, you can easily identify those permissions which are important for connecting SQL Server. I took the reference from this official page.

SELECT 
	EP.name, 
	SP.STATE,   
	CONVERT(nvarchar(38), suser_name(SP.grantor_principal_id)) AS GRANTOR,   
	SP.TYPE AS PERMISSION,  
	CONVERT(nvarchar(46),suser_name(SP.grantee_principal_id)) AS GRANTEE   
FROM sys.server_permissions SP, sys.endpoints EP  
WHERE SP.major_id = EP.endpoint_id  
ORDER BY Permission,grantor, grantee

In this post, I am sharing one script to find the size of Indexes in SQL Server.

The first step for performance optimization is to measure the size of tables and indexes which helps you to find out more about fragmentation.

I have already shared a couple of articles on SQL Server Indexes like: find duplicate indexes, unused indexes and fragmentation of indexes.

You can also access these articles after below T-SQL.

SELECT
	OBJECT_SCHEMA_NAME(i.OBJECT_ID) AS SchemaName
	,OBJECT_NAME(i.OBJECT_ID) AS TableName
	,i.name AS IndexName
	,8 * SUM(au.used_pages) AS IndexSizeInKB
FROM sys.indexes AS i
JOIN sys.partitions AS p 
	ON p.OBJECT_ID = i.OBJECT_ID 
		AND p.index_id = i.index_id
JOIN sys.allocation_units AS au 
	ON au.container_id = p.partition_id
GROUP BY 
	i.OBJECT_ID
	,i.index_id
	,i.name
ORDER BY OBJECT_NAME(i.OBJECT_ID),i.index_id

Other related articles:

SQL Server: Find the total row count and size of the Tables

SQL Server: Script to find Redundant and Duplicate Indexes

SQL Server: Script to find usage of Database Indexes

SQL Server: Script to find Index Average Fragmentation in Percentage

In this post, I am sharing few different scripts to find when was the SQL Server restarted.

The DBAs must know about this because they have to make sure about data consistency.

For example: when SQL Server restarted because of power failure, system failure, update failure or any other reason, We must check the last restarted time of SQL Server. Because from that time, we have to restore data from our backup disks to the actual disk.

When SQL Server restarted, few transactions also rollback. We have to also identify these transactions by knowing the correct time when SQL Server actually restarted.

Using sys.dm_exec_sessions:

SELECT login_time FROM sys.dm_exec_sessions WHERE session_id = 1
GO

Using sys.dm_os_sys_info:

SELECT sqlserver_start_time FROM sys.dm_os_sys_info
GO

Using sys.databases:

SELECT create_date FROM sys.databases WHERE name = 'tempdb' 
GO

Using sys.traces:

SELECT start_time FROM sys.traces WHERE is_default = 1  
GO

Using sysdatabases:

SELECT crdate FROM sysdatabases WHERE name='tempdb'  
GO

In this post, I am sharing a SQL Interview questions for Database Developer. If you are database fresher and working with SQL, you must prepare for string/date operations related questions and answers.

One of the example questions is How to remove New Line Character from a string?

Check the below sample code:

DECLARE @str VARCHAR(100)
SET @str = 'I am Database 
Engineer'

SELECT @str AS With_New_Line

With_New_Line
---------------------
I am Database 
Engineer

SELECT REPLACE(REPLACE(@str, CHAR(13), ''), CHAR(10), '') AS Without_New_Line

Without_New_Line
---------------------------
I am Database Engineer

Whenever you are searching for SQL query optimization tips or prevent SQL injection tips, you can find few common suggestions like: Please do not use Dynamic SQL in your Stored Procedure. Please try to avoid the use of Temp Tables.

I always tell to database developers, please try to avoid the use of Dynamic SQL and Temp Table in your Stored Procedures.

A Temp Table requires additional CPU/IO which degrades the query performance. A Dynamic SQL is not safe against the SQL Injection and It also compiles data every time which requires more Memory.

Here, I am sharing one of the important scripts which gives you list of SQL Server Stored Procedures, which use the Dynamic SQL and Temp Table.
You can easily get the list of Stored Procedures and can make plans of modifying it.

Prepared this script using sys.dm_exec_describe_first_result_set and sys.procedures where error number 4 = Dynamic SQL and error number 10 = Temporary Table.

SELECT  
	SP_Name
	,error_message
	,error_type_desc 
FROM (SELECT schema_name(schema_id)+'.'+name SP_Name FROM sys.procedures) AS T
CROSS APPLY sys.dm_exec_describe_first_result_set (SP_Name, NULL, 0) 
WHERE error_type IN (4,10)

In this post, I am sharing two different scripts to populate attach and detach scripts for all your SQL Server Databases.

When we are migrating our SQL Database Server, we require to move all databases from one server to another server.

If you have a big number of databases, making of individual attach and detach script will take more time.

I have also added script to change database access mode like: Multi_User to Single_User for Detach Process and Single_User to Multi_User for Attach Process.

If your database is in use, you may require to change the database access mode to close all running connections.

Using this script you can populate attach and detach scripts for all databases.
Execute this script to generate detach scripts for all databases:

DECLARE @DatabaseName AS VARCHAR(255)
DECLARE CurDetach CURSOR FOR
  
  SELECT name
  FROM   MASTER.sys.databases
  WHERE  owner_sid > 1;

OPEN CurDetach
FETCH Next FROM CurDetach INTO @DatabaseName
WHILE @@FETCH_STATUS = 0
  BEGIN      
	  PRINT 
		'ALTER DATABASE ' + @DatabaseName + ' SET SINGLE_USER WITH ROLLBACK IMMEDIATE' 
		+ CHAR(10) + ' GO' + CHAR(10) +
		'sp_detach_db ' + @DatabaseName + CHAR(10)
		+ ' GO' + CHAR(10) + 'Print ''Detach of '
		+ @DatabaseName
		+ ' database completed successfully'''
		+ CHAR(10) + ' GO'

      FETCH NEXT FROM CurDetach INTO @DatabaseName
  END

CLOSE CurDetach
DEALLOCATE CurDetach

Execute this script to generate attach scripts for all databases:
You can change your file name or file path using @Filepath variable.

DECLARE @DatabaseName AS VARCHAR(255)
DECLARE @Filepath AS VARCHAR(255)

SET @Filepath = 'C:\SQLDATA\'

DECLARE CurAttach CURSOR FOR
  SELECT name
  FROM   MASTER.sys.databases
  WHERE  owner_sid > 1;

OPEN CurAttach
FETCH Next FROM CurAttach INTO @DatabaseName
WHILE @@FETCH_STATUS = 0
  BEGIN      
	  PRINT 
		'CREATE DATABASE ' + @DatabaseName + ' ON
		(FILENAME = '+ @Filepath + @DatabaseName +'.mdf)
		,(FILENAME = '+ @Filepath + @DatabaseName +'.ldf)
		FOR ATTACH
		GO

		ALTER DATABASE '+ @DatabaseName +' SET MULTI_USER WITH ROLLBACK IMMEDIATE
		GO'
      FETCH NEXT FROM CurAttach INTO @DatabaseName
  END

CLOSE CurAttach
DEALLOCATE CurAttach

In this post, I am sharing one script to find a list of Weekends between given two Dates in SQL Server.

If you are a database developer and reading this post, you should know about the life of DBA.
Database Administrator life is for 24*7 and they have to also set few maintenance tasks over the weekends and holidays.

This script helps to DBA for finding available weekends between the dates so they can set auto-schedule for database maintenance.

Please access few related articles:

A Day in the life of a DBA !

SQL Server 2012: Find First Sunday of Next Month using EOMONTH

DECLARE @beginDate DATE = '20161201'
DECLARE @endDate DATE = '20161231'  
 
DECLARE @Weekend TABLE
(
	Weekend DATE PRIMARY KEY
	,IsWeekend BIT
)
 
WHILE @beginDate <= @endDate 
BEGIN 
INSERT INTO @Weekend 
SELECT 
	@beginDate AS Weekend 
	,(CASE WHEN DATEPART(WEEKDAY, @beginDate) In (7, 1) THEN 1 ELSE 0 END) AS IsWeekend 
	SET @beginDate = DateAdd(Day, 1, @beginDate) 
END
 
SELECT Weekend FROM @Weekend WHERE IsWeekend = 1

In this post, I am sharing one T-SQL Script to take full backup for all the databases of SQL Server.

There are different types of backups and techniques available in the SQL Server, but I always believe in DBA Scripts which you can modify as per your requirements.

Apart from scheduled backups, sometimes DBA requires ad-hoc full backups of databases which they can do using this script.

Script to take full backup of databases:
You can change the path name (‘C:\TempBackup\’) and replace with your path name.

DECLARE @dbName	NVARCHAR (255); 
DECLARE @SQL NVARCHAR(4000); 
 
DECLARE DBBackupCur 
CURSOR FOR 
    SELECT name FROM sys.databases WITH (NOLOCK) 
    WHERE name NOT IN ('master','model','msdb','tempdb')  
    OPTION (RECOMPILE); 
 
OPEN DBBackupCur;     
FETCH NEXT FROM DBBackupCur INTO @dbName 
WHILE (@@fetch_status <> -1) 
BEGIN 
    IF (@@fetch_status <> -2) 
    BEGIN 
        SET @SQL = N'BACKUP DATABASE [' + @dbName + N'] TO DISK = ''C:\TempBackup\' + @dbName + N'.bak'''; 
        EXECUTE sp_executesql @SQL 
        PRINT N'Backup completed: ' + @dbName 
    END; 
    FETCH NEXT FROM DBBackupCur INTO @dbName; 
END; 
CLOSE DBBackupCur; 
DEALLOCATE DBBackupCur; 
GO

Last week, I was exploring few SQL Server forums and found an interesting discussion on the IDENTITY Column of SQL Server.
One of the discussions like How to set IDENTITY to existing column of a Table?

Actually, there is no any specific option for setting IDENTITY to existing Column of a Table.

But there are different tricks to do this, sharing one of the tricks here…

Create a sample table without identity column:

CREATE TABLE tbl_TestIdentity (ID INT, Name VARCHAR(10))

INSERT INTO tbl_TestIdentity VALUES 
(1,'ABC'), (2,'XYZ'),(3,'PQR')
,(4,'WER'),(5,'JKL'),(6,'ZXC')

Check the data:

SELECT *from tbl_TestIdentity

ID          Name
----------- ----------
1           ABC
2           XYZ
3           PQR
4           WER
5           JKL
6           ZXC

Add new IDENTITY Column to table:

ALTER TABLE tbl_TestIdentity ADD ID2 INT IDENTITY (1,1);

Drop old ID Column:

ALTER TABLE tbl_TestIdentity DROP COLUMN ID

Rename new column to old column name:

Exec sp_rename 'tbl_TestIdentity.ID2', 'ID', 'Column'

Result:

SELECT *from tbl_TestIdentity

Name       ID
---------- -----------
ABC        1
XYZ        2
PQR        3
WER        4
JKL        5
ZXC        6

SQL Server: How to remove IDENTITY from a Column?

SQL Server: Script to find Identity Column of a Database