Top 50 Important Queries In SQL Server
In this article I will explain some general purpose SQL queries. I think each developer should have knowledge of these queries. These queries are not related to any specific topic of SQL. But knowledge of such queries can solve some complex tasks and may be used in many scenarios, so I decided to write an article on these queries.
1: Retrieve List of All Database
EXEC sp_helpdb
2: Display Text of Stored Procedure, Trigger, View
exec sp_helptext @objname = 'Object_Name'
3: Get All Stored Procedure Relate To Database
SELECT DISTINCT o.name, o.xtype FROM syscomments c INNER JOIN sysobjects o ON c.id=o.id WHERE o.xtype='P'
To retrieve the View use “V” instead of “P” and for functions use “FN.
4: Get All Stored Procedure Relate To Table
SELECT DISTINCT o.name, o.xtype FROM syscomments c INNER JOIN sysobjects o ON c.id=o.id WHERE c.TEXT LIKE '%Table_Name%' AND o.xtype='P'
To retrieve the View use “V” instead of “P” and for functions use “FN.
5: Rebuild All Index of Database
EXEC sp_MSforeachtable @command1="print '?' DBCC DBREINDEX ('?', ' ', 80)"
GO
EXEC sp_updatestats
GO
6: Retrieve All dependencies of Stored Procedure
This query return all objects name that are using into stored procedure like table, user define function, another stored procedure.
;WITH stored_procedures AS ( SELECT oo.name AS table_name, ROW_NUMBER() OVER(partition by o.name,oo.name ORDER BY o.name,oo.name) AS row FROM sysdepends d INNER JOIN sysobjects o ON o.id=d.id INNER JOIN sysobjects oo ON oo.id=d.depid WHERE o.xtype = 'P' AND o.name LIKE '%SP_NAme%' ) SELECT Table_name FROM stored_procedures WHERE row = 1
7: Find Byte Size Of All tables in database
SELECT sob.name AS Table_Name, SUM(sys.length) AS [Size_Table(Bytes)] FROM sysobjects sob, syscolumns sys WHERE sob.xtype='u' AND sys.id=sob.id GROUP BY sob.name
8: Get all table that don’t have identity column
SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES where Table_NAME NOT IN ( SELECT DISTINCT c.TABLE_NAME FROM INFORMATION_SCHEMA.COLUMNS c INNER JOIN sys.identity_columns ic on (c.COLUMN_NAME=ic.NAME)) AND TABLE_TYPE ='BASE TABLE'
9: List of Primary Key and Foreign Key for Whole Database
SELECT DISTINCT Constraint_Name AS [Constraint], Table_Schema AS [Schema], Table_Name AS [TableName] FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE GO
10: List of Primary Key and Foreign Key for a particular table
SELECT DISTINCT Constraint_Name AS [Constraint], Table_Schema AS [Schema], Table_Name AS [TableName] FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE WHERE INFORMATION_SCHEMA.KEY_COLUMN_USAGE.TABLE_NAME='Table_Name' GO
11: RESEED Identity of all tables
EXEC sp_MSForEachTable '
IF OBJECTPROPERTY(object_id(''?''), ''TableHasIdentity'') = 1
DBCC CHECKIDENT (''?'', RESEED, 0)
12: List of tables with number of records
CREATE TABLE #Tab ( Table_Name [varchar](max), Total_Records int ); EXEC sp_MSForEachTable @command1=' Insert Into #Tab(Table_Name, Total_Records) SELECT ''?'', COUNT(*) FROM ?' SELECT * FROM #Tab t ORDER BY t.Total_Records DESC; DROP TABLE #Tab;
13: Get the version name of SQL Server
SELECT @@VERSION AS Version_Name
14: Get Current Language of SQL Server
SELECT @@LANGUAGE AS Current_Language;
15: Disable all constraints of a table
ALTER TABLE Table_Name NOCHECK CONSTRAINT ALL
16: Disable all constraints of all tables
EXEC sp_MSForEachTable 'ALTER TABLE ? NOCHECK CONSTRAINT ALL'
17: Get Current Language Id
SELECT @@LANGID AS 'Language ID'
18: Get precision level used by decimal and numeric as current set in Server
SELECT @@MAX_PRECISION AS 'MAX_PRECISION'
19: Return Server Name of SQL Server
SELECT @@SERVERNAME AS 'Server_Name'
20: Get name of register key under which SQL Server is running
SELECT @@SERVICENAME AS 'Service_Name'
21: Get Session Id of current user process
SELECT @@SPID AS 'Session_Id'
22: Get Current Value of TEXTSIZE option
SELECT @@TEXTSIZE AS 'Text_Size'
23: Retrieve Free Space of Hard Disk
EXEC master..xp_fixeddrives
24: Disable a Particular Trigger
Syntax ALTER TABLE Table_Name DISABLE TRIGGER Trigger_Name Example ALTER TABLE Employee DISABLE TRIGGER TR_Insert_Salary
25: Enable a Particular Trigger
Syntax ALTER TABLE Table_Name ENABLE TRIGGER Trigger_Name Example ALTER TABLE Employee ENABLE TRIGGER TR_Insert_Salary
26: Disable All Trigger of a table
Syntax ALTER TABLE Table_Name DISABLE TRIGGER ALL Example ALTER TABLE Demo DISABLE TRIGGER ALL
27: Enable All Trigger of a table
Syntax ALTER TABLE Table_Name ENABLE TRIGGER ALL Example ALTER TABLE Demo ENABLE TRIGGER ALL
28: Disable All Trigger for database
Using sp_msforeachtable system stored procedure we enable and disable all triggers for a database.
Syntax Use Database_Name Exec sp_msforeachtable "ALTER TABLE ? DISABLE TRIGGER all"
29: Enable All Trigger for database
Use Demo Exec sp_msforeachtable "ALTER TABLE ? ENABLE TRIGGER all"
30: List of Stored procedure modified in last N days
SELECT name,modify_date FROM sys.objects WHERE type='P' AND DATEDIFF(D,modify_date,GETDATE())< N
31: List of Stored procedure created in last N days
SELECT name,sys.objects.create_date FROM sys.objects WHERE type='P' AND DATEDIFF(D,sys.objects.create_date,GETDATE())< N
32: Recompile a stored procedure
EXEC sp_recompile'Procedure_Name'; GO
33: Recompile all stored procedure on a table
EXEC sp_recompile N'Table_Name'; GO
34: Get all columns of a specific data type
SELECT OBJECT_NAME(c.OBJECT_ID) as Table_Name, c.name as Column_Name FROM sys.columns AS c JOIN sys.types AS t ON c.user_type_id=t.user_type_id WHERE t.name = 'Data_Type'
35: Get all Nullable columns of a table
SELECT OBJECT_NAME(c.OBJECT_ID) as Table_Name, c.name as Column_Name FROM sys.columns AS c JOIN sys.types AS t ON c.user_type_id=t.user_type_id WHERE c.is_nullable=0 AND OBJECT_NAME(c.OBJECT_ID)='Table_Name'
36: Get All table that don’t have primary key
SELECT name AS Table_Name FROM sys.tables WHERE OBJECTPROPERTY(OBJECT_ID,'TableHasPrimaryKey') = 0 ORDER BY Table_Name;
37: Get All table that don’t have foreign key
SELECT name AS Table_Name FROM sys.tables WHERE OBJECTPROPERTY(OBJECT_ID,'TableHasForeignKey') = 0 ORDER BY Table_Name;
38: Get All table that don’t have identity column
SELECT name AS Table_Name FROM sys.tables WHERE OBJECTPROPERTY(OBJECT_ID,'TableHasIdentity') = 0 ORDER BY Table_Name;
39: Get First Date of Current Month
SELECT CONVERT(VARCHAR(25),DATEADD(DAY,-(DAY(GETDATE()))+1,GETDATE()),105) First_Date_Current_Month;
40: Get last date of previous month
SELECT CONVERT(VARCHAR(25),DATEADD(DAY,-(DAY(GETDATE())),GETDATE()),105) Last_Date_Previous_Month;
41: Get last date of current month
SELECT CONVERT(VARCHAR(25),DATEADD(DAY,-(DAY(GETDATE())), DATEADD(MONTH,1,GETDATE())),105) Last_Date_Current_Month;
42: Get first date of next month
SELECT CONVERT(VARCHAR(25),DATEADD(DAY,-(DAY(GETDATE())), DATEADD(MONTH,1,GETDATE())+1),105) First_Date_Next_Month;
43: Swap the values of two columns
UPDATE Table_Name SET Column1=Column2, Column2=Column1
44: Remove all stored procedure from database
Declare @Drop_SP Nvarchar(MAX)
Declare My_Cursor Cursor For Select [name] From sys.objects where type = 'p'
Open My_Cursor
Fetch Next From My_Cursor Into @Drop_SP
While @@FETCH_STATUS= 0
Begin
Exec('DROP PROCEDURE ' + @Drop_SP)
Fetch Next From My_Cursor Into @Drop_SP
End
Close My_Cursor
Deallocate My_Cursor
45: Remove all views from database
Declare @Drop_View Nvarchar(MAX)
Declare My_Cursor Cursor For Select [name] From sys.objects where type = 'v'
Open My_Cursor
Fetch Next From My_Cursor Into @Drop_View
While @@FETCH_STATUS = 0
Begin
Exec('DROP VIEW ' + @Drop_View)
Fetch Next From My_Cursor Into @Drop_View
End
Close My_Cursor
Deallocate My_Cursor
46: Drop all tables
EXEC sys.sp_MSforeachtable @command1 = 'Drop Table ?'
47: Get information of tables’ columns
SELECT * FROM INFORMATION_SCHEMA.COLUMNS WHERE INFORMATION_SCHEMA.COLUMNS.TABLE_NAME=’Table_Name’
48: Get all columns contain any constraints
SELECT TABLE_NAME,COLUMN_NAME,CONSTRAINT_NAME FROM INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE
49: Get all tables that contain a view
SELECT * FROM INFORMATION_SCHEMA.VIEW_TABLE_USAGE
50: Get all columns of table that using in views
SELECT * FROM INFORMATION_SCHEMA.VIEW_COLUMN_USAGE
