CREATE TABLE
	Table1 (
		  Id       INT      NOT NULL
		, SomeDate datetime NULL
		CONSTRAINT [PK_Table1] PRIMARY KEY CLUSTERED ( Id ASC )
	)

-- Combining an INSERT with a SELECT.
INSERT
	Table1 (
		  Col1
		, Col2
		, Col3
	)
SELECT
	  Table2.Col1
	, Table2.Col2
	, Table2.Col3
FROM
	Table2

-- Combining an UPDATE with a SELECT.
UPDATE
	Table1
SET
	  Table1.Col1 = Table2.Col1
	, Table1.Col2 = Table2.Col2
FROM
	Table1
INNER JOIN
	Table2
ON
	Table2.Id = Table1.Id

SELECT
	BestEmployee.Name
FROM (
	SELECT TOP 100
		*
	FROM
		Employee
	ORDER BY
		Employee.Sales DESC
) AS BestEmployee
ORDER BY
	BestEmployee.Name

-- Untested code.
WITH BestEmployee_CTE
AS
(
	SELECT TOP 100
		*
	FROM
		Employee
	ORDER BY
		Employee.Sales DESC
)
SELECT
	BestEmployee.Name
FROM
	BestEmployee_CTE

-- Use *only* if a nested SELECT or CTE won't do the job.
DECLARE @SpecialEmployees TABLE
(
	EmployeeID INT
)
 
INSERT
	@SpecialEmployees (EmployeeID)
SELECT
	Employee.EmployeeID
FROM
	Employee

-- Doesn't copy keys or constraints.
CREATE TABLE 
	NewTable
AS
SELECT
	*
FROM
	SourceTable
-- Omit, if data is also to be copied.
WHERE
	1=2;

ALTER TABLE TABLE_NAME
	ADD Column_Name INT NULL;

IF COL_LENGTH('Table_Name','Column_Name') IS NULL
BEGIN
	ALTER TABLE TABLE_NAME
		ADD Column_Name INT NULL;
END

EXEC sp_rename 'Categories.Active', 'Active_Old', 'COLUMN'

If you want to preserve permissions:

IF OBJECT_ID('StoredProcedure_Name') IS NULL
	EXEC ('CREATE PROCEDURE StoredProcedure_Name AS SELECT 1')
GO
ALTER PROCEDURE StoredProcedure_Name
(
...

If you are happy to blow away permissions:

IF OBJECT_ID('StoredProcedure_Name', 'P') IS NOT NULL
	DROP PROC StoredProcedure_Name
 
GO
CREATE PROCEDURE StoredProcedure_Name
(
...

SELECT * FROM sys.dm_exec_describe_first_result_set(
   N'EXEC SomeStoredProcedure 1234', NULL, 0);

BACKUP DATABASE SourceDatabase
TO DISK = 'E:\Backups\20150609 SourceDatabase.bak'
WITH COPY_ONLY, INIT
 
CREATE DATABASE NewDatabase
 
-- Use the LogicalName column to populate the MOVE clause of the RESTORE DATABASE command.
RESTORE FILELISTONLY FROM DISK = 'E:\Backups\20150609 SourceDatabase.bak' WITH FILE = 1
 
-- Use the physical_name column to populate the TO clause of the RESTORE DATABASE command.
SELECT
	master_files.physical_name
FROM
	master.sys.databases
JOIN
	master.sys.master_files
ON
	master_files.database_id = DATABASES.database_id
WHERE
	DATABASES.name = 'NewDatabase'
 
RESTORE DATABASE NewDatabase
FROM DISK = 'E:\Backups\20150609 SourceDatabase.bak'
WITH REPLACE
	, MOVE 'SourceDatabase' TO N'E:\Program Files\Microsoft SQL Server\MSSQL11.MSSQLSERVER\MSSQL\DATA\NewDatabase.mdf'
	, MOVE 'SourceDatabase_log' TO N'E:\Program Files\Microsoft SQL Server\MSSQL11.MSSQLSERVER\MSSQL\DATA\NewDatabase_log.ldf'
 
-- Compare the databases. No results = no differences.
SELECT
    *
FROM
    SourceDatabase.sys.objects SourceObjects
FULL JOIN
    NewDatabase.sys.objects NewObjects
    ON NewObjects.object_id = SourceObjects.object_id
WHERE
    SourceObjects.object_id IS NULL OR NewObjects.object_id IS NULL

ALTER DATABASE DatabaseName SET SINGLE_USER WITH ROLLBACK IMMEDIATE
GO
 
-- Do this straight away, because it sucks if a database is left in single user mode.
ALTER DATABASE DatabaseName SET MULTI_USER 
GO

-- Find a table in all databases.
sp_msforeachdb @command1='USE ?;SELECT DB_NAME() AS [Database], * FROM sys.Tables WHERE name LIKE ''TableName'''

-- Find a table column in all databases.
sp_msforeachdb @command1='USE ?;SELECT DB_NAME() AS [Database], t.name AS [Table], * FROM sys.Columns c JOIN sys.Tables t ON t.object_id = c.object_id WHERE c.name LIKE ''ColumnName'''

-- No results = no differences. This is only suitable for databases that have been duplicated *exactly*.
SELECT
    *
FROM
    SourceDatabase.sys.objects SourceObjects
FULL JOIN
    TargetDatabase.sys.objects TargetDatabase
    ON TargetDatabase.object_id = SourceObjects.object_id
WHERE
    SourceObjects.object_id IS NULL OR TargetDatabase.object_id IS NULL

SELECT *
FROM
	Foo
INNER JOIN
	History MostRecentHistory
	ON MostRecentHistory.FooId = Foo.Id
LEFT JOIN
	History AllHistory
	ON AllHistory.FooId = MostRecentHistory.FooId
	AND AllHistory.LastUpdateOn > MostRecentHistory.LastUpdateOn
WHERE
	AllHistory.Id IS NULL
 
-- If the Foo table may not have history and all results are still required:
SELECT *
FROM
	Foo
LEFT JOIN
	History MostRecentHistory
	ON MostRecentHistory.FooId = Foo.Id
LEFT JOIN
	History AllHistory
	ON AllHistory.FooId = MostRecentHistory.FooId
	AND AllHistory.LastUpdateOn > MostRecentHistory.LastUpdateOn
WHERE
	AllHistory.Id IS NULL

Use a Nested SELECT Statement or a Common Table Expression instead!

DECLARE @Results TABLE (
	  BananaId   INT
	, BananaName VARCHAR(MAX)
)

Use a Nested SELECT Statement or a Common Table Expression instead!

DECLARE @Results TABLE (
	  BananaId   INT
	, BananaName VARCHAR(MAX)
)
 
INSERT INTO
	@Results
EXEC
	GetRipeBananas

SELECT
	  ReferentialConstraint.CONSTRAINT_NAME        ForeignKey_Name
	, ForeignKey.TABLE_SCHEMA                      ForeignKey_Schema
	, ForeignKey.TABLE_NAME                        ForeignKey_Table
	, ForeignKey.COLUMN_NAME                       ForeignKey_Column
	, ReferentialConstraint.UNIQUE_CONSTRAINT_NAME PrimaryKey_Name
	, PrimaryKey.TABLE_SCHEMA                      PrimaryKey_Schema
	, PrimaryKey.TABLE_NAME                        PrimaryKey_Table
	, PrimaryKey.COLUMN_NAME                       PrimaryKey_Column
	, ReferentialConstraint.MATCH_OPTION           MatchOption
	, ReferentialConstraint.UPDATE_RULE            UpdateRule
	, ReferentialConstraint.DELETE_RULE            DeleteRule
FROM
	INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS ReferentialConstraint
JOIN
	INFORMATION_SCHEMA.KEY_COLUMN_USAGE ForeignKey
	ON ForeignKey.CONSTRAINT_NAME = ReferentialConstraint.CONSTRAINT_NAME
JOIN
	INFORMATION_SCHEMA.KEY_COLUMN_USAGE PrimaryKey
	ON PrimaryKey.CONSTRAINT_NAME = ReferentialConstraint.UNIQUE_CONSTRAINT_NAME

DECLARE @searchText NVARCHAR(MAX) = N'Foo';
DECLARE @SQL NVARCHAR(MAX) = N'';
 
SELECT @SQL = @SQL +
	CONCAT(
		'SELECT '''
		, [TABLE].[name]
		, ''' AS [Table], '''
		, [COLUMN].[name]
		, ''' AS [Column], ['
		, [TABLE].[name]
		, '].['
		, [COLUMN].[name]
		, '] AS [Data] FROM '
		, [TABLE].[name]
		, ' WHERE ['
		, [TABLE].[name]
		, '].['
		, [COLUMN].[name]
		, '] LIKE ''%'
		, @searchText
		, '%'''
		, CHAR(13) + CHAR(10)
		, 'UNION ALL'
		, CHAR(13) + CHAR(10)
	)
FROM
	sys.columns AS [COLUMN]
JOIN
	sys.tables AS [TABLE]
	ON [TABLE].object_id = [COLUMN].object_id
JOIN
	sys.systypes AS ColumnType
	ON ColumnType.xtype = [COLUMN].system_type_id
WHERE
	[ColumnType].[name] IN ('nchar', 'ntext', 'nvarchar', 'text', 'varchar')
ORDER BY
	  [TABLE].[name]
	, [COLUMN].[name]
 
SELECT @SQL = SUBSTRING(@SQL,1, LEN(@SQL) - 11);
EXEC (@SQL)

1. Run the SQL below.
2. Copy the results into the editor.
3. Remove the last UNION ALL.
4. Append the bit at the beginning.

-- DECLARE @searchText NVARCHAR(100) = N'%foo%';
SELECT
	CONCAT(
		  'SELECT '''
		, [TABLE].[name]
		, ''' AS [Table], '''
		, [COLUMN].[name]
		, ''' AS [Column], ['
		, [TABLE].[name]
		, '].['
		, [COLUMN].[name]
		, '] COLLATE '
		, CONVERT(NVARCHAR, serverproperty('collation'))
		, ' AS [Data] FROM ['
		, [TABLE].[name]
		, '] WHERE ['
		, [TABLE].[name]
		, '].['
		, [COLUMN].[name]
		, '] LIKE @searchText UNION ALL'
	)
FROM
	sys.columns AS [COLUMN]
JOIN
	sys.tables AS [TABLE]
	ON [TABLE].object_id = [COLUMN].object_id
JOIN
	sys.systypes AS ColumnType
	ON ColumnType.xtype = [COLUMN].system_type_id
JOIN
	sys.schemas AS [Schema]
	ON [Schema].schema_id = [TABLE].schema_id
WHERE
	[ColumnType].[name] IN ('nchar', 'ntext', 'nvarchar', 'text', 'varchar')
	AND [TABLE].is_ms_shipped = 0
	AND [Schema].[name] = 'dbo'
ORDER BY
	  [TABLE].[name]
	, [COLUMN].[name]

SELECT ABS(CAST(CAST(NEWID() AS VARBINARY) AS INT)) AS RandomNumber
 
SELECT LEFT(CAST(NEWID() AS VARCHAR(100)), 6) AS RandomString
 
-- Semi-random, good for randomish sorting, returns varbinary(8000)
SELECT HashBytes('MD5', CONCAT('Seed', TABLE.TableId))
 
-- Same thing, but returns varchar(32)
SELECT CONVERT(VARCHAR(32), HashBytes('MD5', CONCAT('Seed', TABLE.TableId)), 2)

EXEC sys.xp_fixeddrives

-- Just for general info
EXEC master.dbo.xp_fileexist N'\\PVW-ENT-SQL32\Backups\SMS.bak'
 
-- Part of a script that needs to make a decision.
DECLARE @RESULT INT
EXEC master.dbo.xp_fileexist N'\\PVW-ENT-SQL32\Backups\SMS.bak', @RESULT OUTPUT
IF @RESULT = 1
	PRINT 'File exists.'
ELSE
	PRINT 'File does not exist.'

EXEC Master.dbo.xp_DirTree 'C:',1,1

-- Replace username with the actual username.
USE DATABASE
EXEC sp_change_users_login 'report'
EXEC sp_change_users_login 'auto_fix', 'CIPLogin' -- This definitely works.
-- Or try:
EXEC sp_change_users_login @Action = 'auto_fix', @UserNamePattern = 'User', @Password = 'Password'
EXEC sp_change_users_login 'update_one', username, username
-- Quantate
USE QuantateAdministration
EXEC sp_change_users_login 'update_one', 'QuantateSysAdmin', 'Quantate_Login'
-- CIP
USE CIP
EXEC sp_change_users_login 'update_one', 'CIPUser', 'CIPLogin'
-- NGA Provisioning
USE NextGenProvDB
EXEC sp_change_users_login 'update_one', 'NextGenUser', 'NextGenLogin'
-- General. 
EXEC sp_change_users_login 'update_one', 'DBUser', 'ServerUser'
-- Server -> Security -> Logins -> *ServerUser* -> Right click -> Properties
-- User Mapping -> Find correct database, value in User col = *DBUser*

SELECT TOP 100
	*
FROM
	OpenQuery (LinkedServerName, 'SELECT * FROM Users')

Can do this, but it will only show which tables reference the specified table, not what tables the specified table references:

sp_fkeys TableName

Better to do this, which lists all foreign key relationships and lots of other information as well:

sp_help TableName

This is particularly useful when the database is on Azure.

-- Create the Login.
-- The CHECK_EXPIRATION and CHECK_POLICY options relate to the password. Switch them off for a service or application type login.
CREATE LOGIN [OrchardUser] WITH PASSWORD=N'XXXXXXX', DEFAULT_DATABASE=[master], CHECK_EXPIRATION=OFF, CHECK_POLICY=OFF
GO
 
-- Create the User.
CREATE USER [OrchardUser] FOR LOGIN [OrchardUser] WITH DEFAULT_SCHEMA=[dbo]
GO
 
-- Grant a role.
EXEC sp_addrolemember N'db_owner', N'OrchardUser'

Generates SQL commands to drop everything in the database. Be careful you nuke the correct database…

USE [DATABASE]
 
SELECT 'DROP PROCEDURE ' + [Schema].name + '.' + StoredProcedure.name AS SqlCommand
       , 10                                                           AS SortOrder
FROM   sys.objects StoredProcedure
JOIN   sys.schemas [Schema]
ON     [Schema].schema_id = StoredProcedure.schema_id
WHERE  StoredProcedure.TYPE = 'P'
UNION
SELECT 'DROP VIEW ' + sys.objects.name
       , 20
FROM   sys.objects
WHERE  sys.objects.TYPE = 'V'
UNION
SELECT 'ALTER TABLE ' + [ParentTable].Name + ' DROP CONSTRAINT [' + [ForeignKey].name + ']'
       , 30
FROM   sys.objects [ForeignKey]
JOIN   sys.objects [ParentTable]
ON     [ParentTable].object_id = [ForeignKey].parent_object_id
WHERE  [ForeignKey].TYPE = 'F'
UNION
SELECT 'DROP TABLE ' + sys.objects.name
       , 40
FROM   sys.objects
WHERE  sys.objects.TYPE = 'U'
ORDER BY SortOrder

EXEC sp_who
 
-- Find the spid of the connect that is connected to the database.
KILL 56
 
ALTER DATABASE [DatebaseName] SET MULTI_USER

If only one result set is returned:

using (SqlConnection connection = new SqlConnection("Data Source=...")) {
	connection.Open();
 
	using (SqlCommand command = new SqlCommand("StoredProcedureName", connection)) {
		command.CommandType = CommandType.StoredProcedure;
		command.CommandTimeout = 300;
 
		using (SqlDataReader reader = command.ExecuteReader()) {
			while (reader.Read()) {
				for (int i = 0; i < reader.FieldCount; i++) {
					string fieldName  = reader.GetName(i);
					// Note that values must be accessed by the column index and can not be accessed directly by field name.
					string fieldValue = reader.GetValue(i);
					Console.WriteLine("{0}: {1}", fieldName, fieldValue);
				}
			}
 
			reader.Close();
		}
	}
}

If multiple result sets are returned:

using (SqlConnection connection = new SqlConnection("Data Source=...")) {
	connection.Open();
 
	using (SqlCommand command = new SqlCommand("StoredProcedureName", connection)) {
		command.CommandType = CommandType.StoredProcedure;
		command.CommandTimeout = 300;
 
		using (SqlDataReader reader = command.ExecuteReader()) {
			do {
				while (reader.Read()) {
					for (int i = 0; i < reader.FieldCount; i++) {
						string fieldName  = reader.GetName(i);
						// Note that values must be accessed by the column index and can not be accessed directly by field name.
						string fieldValue = reader.GetValue(i);
						Console.WriteLine("{0}: {1}", fieldName, fieldValue);
					}
				}
 
			// Move to the next set of results.
			} while (reader.NextResult());
 
			reader.Close();
		}
	}
}