Select statement in MS SQL Server
In this article, the most basic statement used in SQL is being discussed.
Basic statement: select
- There are large amounts of data available everywhere.
- The data is stored in a sequential order in form of a table.
- Each table consists of a row which represents a unique record and column represents a field.
- Schemas are used to arrange the tables in a logical order.
- In order to extract particular data from the tables, queries are being used which is written in Structured Query Language(SQL).
- To query data, select statement is used.
Syntax:
select select_list; from schema_name.table.name;
In order to retrieve all the columns from a table, select* is being used.
Syntax - select* from table_name;
Points to remember:
- In the real time databases, select* isn’t recommended for use because it retrieves the data more than your requirements.
- It results in slow functioning of the application.
- In case, the user adds more columns to the table, the select* statement retrieves all the columns including the new ones resulting in crashing of the application.
Example:
Roll number | Name | Course |
---|---|---|
111 | Riya | CSE |
112 | Apoorva | ECE |
113 | Mina | Mech |
114 | Rita | Biotechnology |
115 | Veena | Chemical |
116 | Deepa | EEE |
If the user wants to retrieve the name of the student pursuing Computer Science, the query is as follows:
select name from course.student where course='cse'
Note that course is the name of the schema and student is the name of the table.
The output will be retrieved as follows:
Name | Course |
---|---|
Riya | CSE |
Note –
To retrieve the query, another statement where is being used which will be discussed in further articles.
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