Capablities of SELECT Statements

SELECT statement is used to retrieves information form the database. Oracle, SQL, MySQL etc. supports SELECT statement. As SELECT statement retrieves data, it can do three types of work (1) projection, (2) selection and (3) joining. This page describes the capabilities of SQL SELECT statements.

Capabilities of SELECT statement:

SQL SELECT statement can do the following three types of work:

  • Projection
  • Selection
  • Joining

All of them are described below:

Projection

By using SQL SELECT statement you can project or select all or the specific columns. It's primary goal is to select only the columns. The selected columns may be all the columns of the table. You can choose few or all the columns according to your queries.

Using SELECT statement, you can select all or several columns of a table. The orange column of this picture means that only those columns are selected.
Using SELECT statement, you can select all or several columns of a table. The orange column of this picture means that only those columns are selected.
Using SELECT statement, you can select specific rows of a table. The orange rows of this picture means that only those rows are selected.
Using SELECT statement, you can select specific rows of a table. The orange rows of this picture means that only those rows are selected.

Selection

By using SELECT statement, you can select the specific no of rows form the table. You can restrict the rows by applying several conditions. In this case, SELECT statement is used as filtering.

Joining

By using SELECT statement, you can join different types of table. Use join capabilities to bring together data that is stored in different tables by creating a link between different tables.

Summary of SELECT statements

SELECT statements can retrieve data by 3 ways:

  • Projection: Select columns
  • Selection: Select rows
  • Joining: Join different tables data

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Rohullah 4 years ago

Thanks a lot rancid Taste

its really need full

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