SQL SELECT Statement

To select all the columns from a Table, so it is converted into

SELECT *
FROM Production.Product;

In Microsoft SQL Server, you follow the convention as –

FROM DatabaseName.SchemaName.TableName

Suppose your database name is AdventureWorks2017, Schema Name is Production and Table name is Product and you are already connected to the database, then you do not need to type –

FROM AdventureWorks2017.Production.Product

because you are already connected to AdventureWorks2017 database.

So, you can simply code –

FROM Production.Product

Note It is optional to place a semicolon(;) at the end of a SQL statement but I strictly follow that each of my SQL statements should end with a semicolon(;) because the Semicolon suggests the end of a query and is a better way of coding.
The SQL standard to terminate a query is to use a semicolon at the end of the query and some of the databases strictly require you to place a semicolon at the end of the query.

Order Of execution in SQL

Even though the SELECT statement comes first but the SQL server Engine considers the FROM clause first and then processes the SELECT clause.

So, when you code –

SELECT *
FROM Production.Product;

Microsoft SQL Server engine will process the FROM clause first and then followed by SELECT clause.

i.e. 1.FROM -> 2.SELECT

Note SQL queries/Statements are NOT Case Sensitive.

So, when you code –

SELECT *
FROM Production.Product;

It is same as –

Select *
FROM Production.Product;

or, it is same as –

SELECt *
FroM Production.Product;

Tips
But, I strongly suggest to use Capital letters for all the SQL keywords like SELECT, FROM, etc.

Note Always try to select only the required columns instead of selecting all the columns of the table.

Selecting Individual column or multiple columns

If you wish to select all the records of ‘CountryRegionCode’ column from ‘CountryRegion’ table which is present under the ‘Person’ schema, then you can code the SQL Query as –

SELECT CountryRegionCode
FROM Person.CountryRegion;

If you also wish to select all the records of ‘Name’ and ‘CountryRegionCode’ columns from ‘CountryRegion’, then you can code the SQL Query as –

SELECT CountryRegionCode, Name
FROM Person.CountryRegion;

Note The order of the columns is important because this query is not same as:

SELECT Name, CountryRegionCode
FROM Person.CountryRegion;

Selecting column which has spaces in it

In Microsoft SQL Server, if you have a column name that contains a space, then, you have to surround that particular column name within square brackets.

For example, if you have a table with the name as ‘Customers’ under the Schema ‘Person’ and you have a column with the name as ‘First Name’
Then, you have to select the records from that particular column name as –

SELECT [First Name]
FROM Person.Customers;

Note When you will go to Create Tables article, you will understand the naming convention for Column Names, Table, etc but at this moment, it is important to remember that if you have a column name which has special characters like space, hyphens, etc then you have to keep those column names within the opening and close of Square brackets like [column name]. If you miss to enclose these types of columns in square brackets, the SQL Editor will throw an ERROR!

Literal SELECT

It is important to understand that if you code column names inside 2 single quotes, then it is called Literal SELECT. Literal select means select ‘AS IT IS’. For Example –

Example

SELECT 'First Name' 
FROM Person.Person;