Advertisements

Archive

Archive for the ‘SQL’ Category

How to implement SQL Bulk Copy in SQL Server OR Bulk insert into SQL Server using SQL BulkCopy

October 17, 2012 1 comment

SqlBulkCopy for insert multiple rows of data into table in SQL Server

Sometimes we need to insert bulk amount of data into a table in SQL. We can insert bulk data to SQL in different methods. Here we are going to demonstrate how to insert large amount of data using SQL Bulk Copy method.

Example of SQL BulkCopy method

Here we are going to insert multiple rows of sample data into Employee table. First of all create a table in SQL named Employee. After that  create sample data for employee table and finally this multiple rows of employee data insert into table using SQL bulk copy method.

Create a Table in SQL 

CREATE TABLE Employee
(
ID INT,
EmpName varchar(200),
Department varchar(200),
DOB DateTime
);

SQLMulkCopy Example in SQL Server

SQLMulkCopy Example in SQL Server

C# Code to generate sample data and insertion using SQL Bulk Copy

private void loadDataBySQLBulkCopy()
        {
            DataTable dtTblEmployee = new DataTable();
            dtTblEmployee.Columns.Add("ID", typeof(Int32));
            dtTblEmployee.Columns.Add("EmpName", typeof(String));
            dtTblEmployee.Columns.Add("Department", typeof(String));
            dtTblEmployee.Columns.Add("DOB", typeof(DateTime));

            DataRow dtrow = dtTblEmployee.NewRow(); // Create New Row
            dtrow["ID"] = 1; //Bind Data to Columns
            dtrow["EmpName"] = "Wazeem";
            dtrow["Department"] = "Admin";
            dtrow["DOB"] = "1990-10-16 12:00:00.000";
            dtTblEmployee.Rows.Add(dtrow);

            dtrow = dtTblEmployee.NewRow(); // Create New Row
            dtrow["ID"] = 2; //Bind Data to Columns
            dtrow["EmpName"] = "Aslam";
            dtrow["Department"] = "HR";
            dtrow["DOB"] = "1987-05-16 12:00:00.000";
            dtTblEmployee.Rows.Add(dtrow);

            dtrow = dtTblEmployee.NewRow(); // Create New Row
            dtrow["ID"] = 3; //Bind Data to Columns
            dtrow["EmpName"] = "John";
            dtrow["Department"] = "Finance";
            dtrow["DOB"] = "1992-12-11 12:00:00.000";
            dtTblEmployee.Rows.Add(dtrow);

            dtrow = dtTblEmployee.NewRow(); // Create New Row
            dtrow["ID"] = 4; //Bind Data to Columns
            dtrow["EmpName"] = "Mishal";
            dtrow["Department"] = "Infra structure";
            dtrow["DOB"] = "1989-04-01 12:00:00.000";
            dtTblEmployee.Rows.Add(dtrow);

            SqlBulkCopy bulkCopy = new SqlBulkCopy(
                "server=TEST;database=TEST;uid=test;password=test",
                SqlBulkCopyOptions.TableLock);
            bulkCopy.DestinationTableName = "dbo.Employee";
            bulkCopy.WriteToServer(dtTblEmployee);

        }

Advertisements

Example for All Types of SQL JOIN (Inner Join, Cross Join, Outer Join, Self Join)

September 9, 2012 Leave a comment

Definition and very simple examples for each JOINS in SQL

Here we are demonstrating with examples  all types of JOINS in SQL Server.  First of all we created sample tables and as per the table data we are explaining each SQL JOINS with most understandable examples.

Sample tables

In the following tables, Department.DepartmentID is the primary key, while Employee.DepartmentID is a foreign key.

Employee Table

LastName

DepartmentID

Rafferty

31

Jones

33

  Steinberg

33

Robinson

34

Smith

34

Jasper

NULL

Department Table

DepartmentID

DepartmentName

31

Sales

33

Engineering

34

Clerical

35

Marketing

Inner join

An inner join requires each record in the two joined tables to have a matching record. An inner join essentially combines the records from two tables (A and B) based on a given join-predicate. The result of the join can be defined as the outcome of first taking the Cartesian product (or cross-join) of all records in the tables (combining every record in table A with every record in table B) – then return all records which satisfy the join predicate.

SQL specifies two different syntactical ways to express joins. The first, called “explicit join notation”, uses the keyword JOIN, whereas the second uses the “implicit join notation”. The implicit join notation lists the tables for joining in the FROM clause of a SELECT statement, using commas to separate them. Thus, it specifies a cross-join, and the WHERE clause may apply additional filter-predicates. Those filter-predicates function comparably to join-predicates in the explicit notation.

One can further classify inner joins as equi-joins, as natural joins, or as cross-joins (see below).

Example of an explicit inner join:

SELECT *
FROM   employee
       INNER JOIN department
          ON employee.DepartmentID = department.DepartmentID
Is equivalent to:
SELECTFROM   employee, department
WHERE  employee.DepartmentID = department.DepartmentID

Explicit Inner join result:

Employee.

LastName

Employee.

DepartmentID

Department.

DepartmentName

Department.

DepartmentID

Smith

34

Clerical

34

Jones

33

Engineering

33

Robinson

34

Clerical

34

Steinberg

33

Engineering

33

Rafferty

31

Sales

31

Types of inner joins

Equi-join

An equi-join, also known as an equijoin, is a specific type of comparator-based join, or theta join, that uses only equality comparisons in the join-predicate. Using other comparison operators (such as <) disqualifies a join as an equi-join.

SELECT Employee.lastName, Employee.DepartmentID, Department.DepartmentName
FROM Employee INNER JOIN Department
ON Employee.DepartmentID = Department.DepartmentID;
SQL provides optional syntactic sugar for expressing equi-joins,
by way of the USING construct (Feature ID F402):
SELECT Employee.lastName, DepartmentID, Department.DepartmentName
FROM Employee INNER JOIN Department
USING(DepartmentID);

The USING clause is supported by MySQL, Oracle and PostgreSQL.

Natural join

A natural join offers a further specialization of equi-joins. The join predicate arises implicitly by comparing all columns in both tables that have the same column-name in the joined tables. The resulting joined table contains only one column for each pair of equally-named columns.

The above sample query for inner joins can be expressed as a natural join in the following way:

SELECT *
FROM   employee NATURAL JOIN department

The result appears slightly different, however, because only one DepartmentID column occurs in the joined table.

DepartmentID

Employee.LastName

Department.DepartmentName

34

Smith

Clerical

33

Jones

Engineering

34

Robinson

Clerical

33

Steinberg

Engineering

31

Rafferty

Sales

Cross join

cross joincartesian join or product provides the foundation upon which all types of inner joins operate. A cross join returns the cartesian product of the sets of records from the two joined tables. Thus, it equates to an inner join where the join-condition always evaluates to True or join-condition is absent in statement.

If A and B are two sets, then the cross join is written as A × B.

The SQL code for a cross join lists the tables for joining (FROM), but does not include any filtering join-predicate.

Example of an explicit cross join:

SELECT *
FROM   employee CROSS JOIN department

Example of an implicit cross join:

SELECT *

FROM   employee, department;

Employee.

LastName       

Employee.

DepartmentID 

Department.

DepartmentName

Department.

DepartmentID

Rafferty

31

Sales

31

Jones

33

Sales

31

Steinberg

33

Sales

31

Smith

34

Sales

31

Robinson

34

Sales

31

Jasper

NULL

Sales

31

Rafferty

31

Engineering

33

Jones

33

Engineering

33

Steinberg

33

Engineering

33

Smith

34

Engineering

33

Robinson

34

Engineering

33

Jasper

NULL

Engineering

33

Rafferty

31

Clerical

34

Jones

33

Clerical

34

Steinberg

33

Clerical

34

Smith

34

Clerical

34

Robinson

34

Clerical

34

Jasper

NULL

Clerical

34

Rafferty

31

Marketing

35

Jones

33

Marketing

35

Steinberg

33

Marketing

35

Smith

34

Marketing

35

Robinson

34

Marketing

35

Jasper

NULL

Marketing

35

Outer joins

An outer join does not require each record in the two joined tables to have a matching record. The joined table retains each record—even if no other matching record exists. Outer joins subdivide further into left outer joins, right outer joins, and full outer joins, depending on which table(s) one retains the rows from (left, right, or both).

Left outer join

The result of a left outer join (or simply left join) for tables A and B always contains all records of the “left” table (A), even if the join-condition does not find any matching record in the “right” table (B). This means that if the ON clause matches 0 (zero) records in B, the join will still return a row in the result—but with NULL in each column from B. This means that a left outer join returns all the values from the left table, plus matched values from the right table (or NULL in case of no matching join predicate).

SELECTFROM   employee  LEFT OUTER JOIN department 
          ON employee.DepartmentID = department.DepartmentID

Employee.

LastName

Employee.

DepartmentID

Department.

DepartmentName

Department.

DepartmentID

Jones

33

Engineering

33

Rafferty

31

Sales

31

Robinson

34

Clerical

34

Smith

34

Clerical

34

Jasper

NULL

NULL

NULL

Steinberg

33

Engineering

33

Right outer joins

right outer join (or right join) closely resembles a left outer join, except with the tables reversed. Every row from the “right” table (B) will appear in the joined table at least once. If no matching row from the “left” table (A) exists, NULL will appear in columns from A for those records that have no match in A.

A right outer join returns all the values from the right table and matched values from the left table (NULL in case of no matching join predicate).
SELECT *
FROM   employee RIGHT OUTER JOIN department
          ON employee.DepartmentID = department.DepartmentID

Employee.

LastName

Employee.

DepartmentID

Department.

DepartmentName

Department.

DepartmentID

Smith

34

Clerical

34

Jones

33

Engineering

33

Robinson

34

Clerical

34

Steinberg

33

Engineering

33

Rafferty

31

Sales

31

NULL

NULL

Marketing

35

In practice, explicit right outer joins are rarely used, since they can always be replaced with left outer joins and provide no additional functionality.

Full outer join

full outer join combines the results of both left and right outer joins. The joined table will contain all records from both tables, and fill in NULLs for missing matches on either side.

For example, this allows us to see each employee who is in a department and each department that has an employee, but also see each employee who is not part of a department and each department which doesn’t have an employee.

Example full outer join:

SELECT *    
FROM   employee
       FULL OUTER JOIN department
          ON employee.DepartmentID = department.DepartmentID

Employee.

LastName

Employee.

DepartmentID

Department.

DepartmentName

Department.

DepartmentID

Smith

34

Clerical

34

Jones

33

Engineering

33

Robinson

34

Clerical

34

Jasper

NULL

NULL

NULL

Steinberg

33

Engineering

33

Rafferty

31

Sales

31

NULL

NULL

Marketing

35

 

Self-join

A self-join is joining a table to itself.

Example

A query to find all pairings of two employees in the same country is desired. If you had two separate tables for employees and a query which requested employees in the first table having the same country as employees in the second table, you could use a normal join operation to find the answer table. However, all the employee information is contained within a single large table.

Considering a modified Employee table such as the following:

Employee Table

EmployeeID

LastName

Country

DepartmentID

123

Rafferty

Australia

31

124

Jones

Australia

33

145

Steinberg

Australia

33

201

Robinson

United States

34

305

Smith

United Kingdom

34

306

Jasper

United Kingdom

NULL

An example solution query could be as follows:

SELECT F.EmployeeID, F.LastName, S.EmployeeID, S.LastName, F.Country
FROM Employee F, Employee S
WHERE F.Country = S.Country
AND F.EmployeeID < S.EmployeeID
ORDER BY F.EmployeeID, S.EmployeeID;

Which results in the following table being generated.

Employee Table after Self-join by Country

EmployeeID

LastName

EmployeeID

LastName

Country

123

Rafferty

124

Jones

Australia

123

Rafferty

145

Steinberg

Australia

124

Jones

145

Steinberg

Australia

305

Smith

306

Jasper

United Kingdom

 

How to delete large amount of rows from table in SQL

September 4, 2012 10 comments

How to delete huge amount of data from a table in SQL

In some scenario we have to delete large amount of rows from sql table and it will going to timeout if the table has very large amount of rows (Some tables in the database has more than crore rows). In this scenario we need to delete some small amount of records and from the table and continue the process until all records in the table deleted.

Query for recursive deletion from the table in SQL 

Below codes delete 50000 rows recursively untill all records int the table deleted. So it never meets the timeout exception and will complete execution faster than normal query

WHILE exists (
SELECT * FROM myTable WHERE name like ‘%ab%’
 )
DELETE TOP (50000) scanned_cont_dtls WHERE name like ‘%ab%’;

How to Create and use Table-Valued Parameter in C# and T-SQL/ How to pass table to stored procedures in SQL

July 17, 2012 Leave a comment

What is Table – Valued Parameter in SQL Server 2008?

Table-valued parameters provide an easy way to marshal multiple rows of data from a client application to SQL Server without requiring multiple round trips or special server-side logic for processing the data. You can use table-valued parameters to encapsulate rows of data in a client application and send the data to the server in a single parameterized command. The incoming data rows are stored in a table variable that can then be operated on by using Transact-SQL.

What we are going to do with Table – Valued Parameter?

We are going to demonstrate a very simple example for using Table – Valued parameter. In this sample project we will insert bulk amount of data into the table by passing a bulk data using datatable in C# to SQL stored procedure.

Create a Table for insert data using Table – Valued Parameter 

Here we are having a table named Officer and having three fields ID,Name and Salary. We are going to fill the table with bulk data.

CREATE TABLE Officer(
ID INT PRIMARY KEY IDENTITY(1,1),
NAME VARCHAR(50),
SALARY DECIMAL(18, 0))

Stored Procedure for insert data by accepting Table Valued Parameter

Now we are going to create a Stored Procedure that accepting a table type as parameter and insert values in this type into the table.

CREATE PROCEDURE InsertOfficerDetails
(
@OfficerData OfficerDetails readonly
)
AS 
INSERT INTO Officer (Name, Salary)
SELECT Name, Salary
FROM @OfficerData;

C# code to call Stored Procedure to insert data in to the table using Table – Valued Parameter

We are creating a simple ASPX page with a single button. When we click this button we are calling above stored procedure by creating and passing some amount of sample data to the stored procedure as Table – Valued Parameter.

ASPX Page 

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="CallSP.aspx.cs" 
Inherits="ExperimentLab.CallSP" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
 <title></title>
</head>
<body>
 <form id="form1" runat="server">
 <div>
 <asp:Button ID="btnCallSP" runat="server" Text="Call SP" 
 OnClick="btnCallSP_Click" />
 </div>
 </form>
</body>
</html>

Code Behind

protected void btnCallSP_Click(object sender, EventArgs e)
 {
 try
 {
 DataTable dt = new DataTable();
 DataColumn dtCol = new DataColumn();
 dtCol.ColumnName = "ID";
 dt.Columns.Add(dtCol);
dtCol = new DataColumn();
 dtCol.ColumnName = "Name";
 dt.Columns.Add(dtCol);
dtCol = new DataColumn();
 dtCol.ColumnName = "Salary";
 dt.Columns.Add(dtCol);
for (int i = 0; i < 10; i++)
 {
 DataRow dr = dt.NewRow();
 dr["Name"] = "Name " + i;
 dr["Salary"] = 1000 + i;
 dr["ID"] = i;
 dt.Rows.Add(dr);
 }
 
 string connStr = ConfigurationManager.
 AppSettings["LocalSqlServer"].ToString();
 SqlConnection con = new SqlConnection(connStr);
using (var conn = new SqlConnection(connStr))
 using (var cmd = conn.CreateCommand())
 {
 cmd.Connection = con;
 con.Open();
 cmd.CommandType = CommandType.StoredProcedure;
 cmd.CommandText = "dbo.InsertOfficerDetails";
 SqlParameter param = cmd.Parameters.AddWithValue("@OfficerData", dt);
 cmd.ExecuteNonQuery();
 }
 }
 catch (Exception a)
 {
 Response.Write(a.Message);
 }
 }

Web.Config

<appSettings>
 <add key="LocalSqlServer" 
value="Database=testDB;Server=Servername\SQLEXPRESS;User Id=userid;Password=password"/>
</appSettings>

Hence we discussed about how to create and use Table valued parameters, how to create a store procedure with table type as parameter, how to pass table to stored procedure in C#/Asp.Net,  how to insert multiple rows of data to a table with table valued parameter in SQL, how to insert bulk data to SQL table using Table Valued Parameter in SQL Server 2008 etc..

 

How to UNPIVOT table in SQL Server / UNPIVOT table example in SQL Server

July 12, 2012 10 comments

What is PIVOT and UNPIVOT operator in SQL Server 

We can use the PIVOT and UNPIVOT relational operators to change a table-valued expression into another table. PIVOT rotates a table-valued expression by turning the unique values from one column in the expression into multiple columns in the output, and performs aggregations where they are required on any remaining column values that are wanted in the final output.

Please go through our previous post for PIVOT sample in SQL

Before UNPIVOT

UNPIVOT sample in SQL Server

Before UNPIVOT table

After UNPIVOT

UNPIVOT sample in SQL Server

UNPIVOT sample in SQL Server

A simple UNPIVOT sample in SQL Server

Here we are going to demonstrate a very simple UNPIVOT sample without any complexity. We are having a table named EmploymentHistory and its containing employee name with previous company name that particular employee worked.

Table Structure For showing simple UNPIVOT sample

CREATE TABLE EmploymentHistory 
(Id INT, 
Employee VARCHAR(500), 
Company1 VARCHAR(500), 
Company2 VARCHAR(500), 
Company3 VARCHAR(500)
) 
GO

-- Load Sample data
INSERT INTO EmploymentHistory SELECT 
1, 'John', 'Tata Motors', 'Ashok Leyland', 'Suzuki'
UNION ALL SELECT 
2, 'Kate', 'Airtel', 'Vodafone', 'Tata Docomo'
UNION ALL SELECT 
3, 'Sam', 'Hercules', 'Hero', 'Atlas'
GO

In order to UNPIVOT above table we can use below mentioned script. The result should be as Employee with each company as a single row.

SELECT Id, 
ROW_NUMBER()OVER(Order By ID) as NewID,
Employee, 
Company
FROM 
( 
SELECT Id, Employee, Company1, Company2, Company3
FROM EmploymentHistory 
) Main
UNPIVOT
( 
Company FOR Companies IN (Company1, Company2, Company3) 
) Sub

UNPIVOT Table with multiple columns

Now we are going to UNPIVOT table with multiple columns. Suppose we are having a table with Employee name, list of company names that particular employee worked and corresponding cities also. The table structure like below.

CREATE TABLE EmploymentHistoryWithCity 
(Id INT, 
Employee VARCHAR(500), 
Company1 VARCHAR(500), 
Company2 VARCHAR(500), 
Company3 VARCHAR(500),
City1 VARCHAR(500), 
City2 VARCHAR(500), 
City3 VARCHAR(500) 
) 
GO
-- Load Sample data 
INSERT INTO EmploymentHistoryWithCity SELECT
1, 'John', 'Tata Motors', 'Ashok Leyland', 'Suzuki', 'Mumbai', 'Kolkata', 'Delhi'
UNION ALL SELECT 
2, 'Kate', 'Airtel', 'Vodafone', 'Tata Docomo', 'Chennai', 'Kolkata', 'Banglore'
UNION ALL SELECT 
3, 'Sam', 'Hercules', 'Hero', 'Atlas', 'Delhi', 'Mumbai', 'Banglore'
GO
UNPIVOT sample in SQL Server

Before UNPIVOT multiple columns table

 

In order to UNPIVOT above table we can use below mentioned script. The result should be as Employee name with Company1 and City1 as a first row, Employee Name with Company2 and City2 as second row and so on
SELECT Id, 
ROW_NUMBER()OVER(Order By ID) as NewID,
Employee, 
Company, 
City 
FROM 
( 
SELECT Id, Employee, Company1, Company2, Company3, City1, City2, City3
FROM EmploymentHistoryWithCity 
) Main
UNPIVOT 
( 
Company FOR companies IN (Company1, Company2, Company3) 
) Sup
UNPIVOT 
( 
City For Cities IN (City1, City2, City3 ) 
) Ct
WHERE RIGHT(companies,1) = RIGHT(Cities,1)
UNPIVOT sample in SQL Server

After UNPIVOT multiple columns table 

 

How to PIVOT table in SQL Server / PIVOT table example in SQL Server

July 10, 2012 2 comments

What is PIVOT and UNPIVOT operator in SQL Server 

We can use the PIVOT and UNPIVOT relational operators to change a table-valued expression into another table. PIVOT rotates a table-valued expression by turning the unique values from one column in the expression into multiple columns in the output, and performs aggregations where they are required on any remaining column values that are wanted in the final output.

Please go through our post for simple UNPIVOT example

Before PIVOT

Before PIVOT table

After PIVOT

After PIVOT table

A simple PIVOT sample in SQL Server

Here we are going to demonstrate a very simple PIVOT sample without any complexity. We are having a table named Accounts and it containing customer name and their deposit with denominations.

Table Structure For showing simple PIVOT sample

CREATE TABLE Accounts(Customer VARCHAR(25), Denomination VARCHAR(20), QTY INT)
GO
-- Inserting Data into Table
INSERT INTO Accounts(Customer, Denomination, QTY)
VALUES('John','10 $',2)
INSERT INTO Accounts(Customer, Denomination, QTY)
VALUES('John','50 $',6)
INSERT INTO Accounts(Customer, Denomination, QTY)
VALUES('John','100 $',1)
INSERT INTO Accounts(Customer, Denomination, QTY)
VALUES('Ram','10 $',4)
INSERT INTO Accounts(Customer, Denomination, QTY)
VALUES('Ram','50 $',3)
INSERT INTO Accounts(Customer, Denomination, QTY)
VALUES('Ram','100 $',11)
INSERT INTO Accounts(Customer, Denomination, QTY)
VALUES('KATE','10 $',20)
INSERT INTO Accounts(Customer, Denomination, QTY)
VALUES('KATE','50 $',12)
INSERT INTO Accounts(Customer, Denomination, QTY)
VALUES('KATE','100 $',2)
INSERT INTO Accounts(Customer, Denomination, QTY)
VALUES('Eby','10 $',0)
INSERT INTO Accounts(Customer, Denomination, QTY)
VALUES('Eby','50 $',5)
INSERT INTO Accounts(Customer, Denomination, QTY)
VALUES('Eby','100 $',5)

In order to PIVOT above mentioned table we can use below script. The result should be as Customer name with all denomination will be coming as columns with qty as values for each column.

SELECT * FROM Accounts
PIVOT (SUM(QTY) For Denomination IN ([10 $],[50 $],[100 $])) AS Total

Dynamic Query to PIVOT table for dynamic columns 

In the above example we are using a simple structured table and then PIVOT with denomination values. This can be achieved only when we are having denomination values as static. Suppose this denomination values are dynamic (Each country having different denomination like $,EUR, IND etc..), we need to create a dynamic query to PIVOT above table.

Suppose we are having different table for getting Denomination values and we are going to take Denomination values from this table at run time as dynamic.

CREATE TABLE Denomination(Value VARCHAR(25))
GO
INSERT INTO Denomination(Value)
VALUES('10 $')
INSERT INTO Denomination(Value)
VALUES('50 $')
INSERT INTO Denomination(Value)
VALUES('100 $')

First of all, we need to get dynamic columns names from the above table. After that we can create a dynamic query with these columns.

Declare @ColumnNames VARCHAR(100);
SELECT @ColumnNames = COALESCE(@ColumnNames+ ',','') +
'['+ Cast(Value AS VARCHAR(50)) +']' FROM Denomination cust
PRINT @ColumnNames
DECLARE @DynamicQuery Varchar(MAX);
SET @DynamicQuery = '
SELECT * FROM Accounts
PIVOT (SUM(QTY) For Denomination IN (' + @ColumnNames + ')) AS Total'
EXEC (@DynamicQuery);

How to Calculate Age in Sql Server OR Find age using SQL query

July 3, 2012 2 comments

Calculate age of employee using SQL Server

To calculate an age from the SQL table is little bit tricky.  We are demonstrating how to calculate the age from the date of birth fields in the SQL table. While fill the application form it’s better to fill the Date Of Birth field instead of age field. Because age field can calculate from the Date Of Birth field easily and accurately.

Find the age from the Date Of Birth using SQL Server

Here we are having a table called Employee and having coloumns ID,Name and DOB. From this table we need to find the age of each employee using SQL script.

 

Please see the table structure.

Calculate age from SQL Server

We can use Date Diff function in SQL Server to get the age of each employee. But if we consider date field only it will get wrong answer because it will consider the current year even date of birth not came this year. The below script and result is example.

 

Calculate age from SQL Server

 

For avoiding above mentioned issue, we can use below script to find out the age from the Date Of Birth field using SQL Server.

SELECT DOB AS DateOfBirth,
GETDATE() AS CurrentDate,
DATEDIFF(YEAR,DOB,GETDATE()) - 
(CASE WHEN 
 DATEADD(YY,DATEDIFF(YEAR,DOB,GETDATE()),DOB) > GETDATE()
 THEN 1
 ELSE 0 END) AS Age
FROM Employee
Find the age using SQL Server

Calculate age using SQL Server


								
%d bloggers like this: