Inserting data into SQL table

Go through Create table script in SQL post to know about how to create the table.

In order to to insert the data into table we will use INSERT command.
Now, we are going to insert data into Employee table that we have created in Create table script in SQL post.

There are alternative ways to insert data into table:
Alternate1:
  INSERT INTO dbo.Employee 
  (
[EmpID]
,[FirstName]
,[LastName]
,[Salary]
  )
  VALUES 
  (
1
,'Anil'
,'Kumar'
,10000
  )
This is the best way to insert data into our table.
Because with this script we can identify which data we are inserting into which column.
We can also change the order of columns in insert script and can insert data accordingly.
Alternative2:
  INSERT INTO dbo.Employee 
  VALUES
  (
1
,'Anil'
,'Kumar'
,10000
  )
In this way we should know what is the ordering of columns inside the table in advance. 
As per the ordering of the columns it will insert the data into table.
Alternative3:
INSERT INTO dbo.Employee 
SELECT 
[EmpID]
,[FirstName]
,[LastName]
,[Salary] 

FROM dbo.Employee 

Inserting multiple rows at a time:
If you want to insert multiple values at a time them you can do it as shown below:
INSERT INTO dbo.Employee 
  VALUES
  ('1', 'Anil', 'Kumar', 10000)
  ,('2', 'Suresh', 'T', 10000)
  ,('3', 'Kumar', 'Anil', 10000)

In this way, you are selecting all the data available in Employee table and then reinserting it into Employee table.
Here i have taken the example of selecting data from Employee table but you can select from any table and insert it into Employee table.

If any column in Nullable then you can choose to ignore that column in your script, it will automatically insert NULL values in those columns but we should definitely insert some data into NOT NULL columns.

Create table script in SQL

In order to create table in SQL we have to use CREATE keyword.

To create a table we need to have below details in hand with us:

a. You should know what should be the table name

b. What are all the columns required in your table

c. Data types of all those columns

d. Constraints of every column, we will learn about different constraints available in SQL in separate post. As of now I will mention whether column accept NULL values or not

Syntax:

CREATE TABLE <<tableName>>

(

<<columnName>> <<dataType>> <<constraint>>

)

Find below Employee table creation script:

CREATE TABLE Employee

(

     EmpID INT NOT NULL

    ,FirstName NVARCHAR(250) NOT NULL

    ,LastName NVARCHAR(250) NULL

    ,Salary MONEY

)

On execution of above script table will be created in the database in below format:

EmpID

FirstName

LastName

Salary

If we see the above script, we have declared EmpID and FirstName as NOT NULL and other two columns as NULL that means those two fields are not mandatory to fill.

In SQL if we don't mention anything then the default constraint will be taken as NULL that is the reason for Salary field the default constraint will be NULL.