The abbreviation for Structured Query Language (SQL) stands for Structured Query Language. SQL commands tell a database how to conduct functions, operations, and queries on data. SQL commands can be used to search the database as well as to create tables, change data, add data to tables, and drop tables. If you’re going to work with SQL, you should know how to use the following commands of SQL. These are the top five commands used most frequently in SQL. But before we get started, let’s go over a brief overview of SQL.
What is SQL?
The SQL language is the industry standard to deal with Relational Databases. Updating, searching, inserting, and deleting database records are all possible with SQL. SQL may do a variety of different tasks, including maintenance and database optimization.
What is the purpose of SQL?
The following are the compelling reasons to use SQL.
It enables users to access data stored in an RDBMS or relational database management system.
It enables you to define data in a database.
It aids in the description of data.
SQL allows you to delete and create databases and tables.
SQL allows you to build a view, a stored procedure, and a function in a database.
Permissions can be configured on tables, processes, and views.
Top 5 Commands of SQL: The top five SQL commands are listed here.
SELECT and FROM: A query’s SELECT clause determines which data columns should be displayed in the results. Options can also be used to display data that isn’t contained in a table column. The sample below shows three columns SELECTED FROM the “student” database and one calculated column. The database stores the studentID, FirstName, and LastName of each student. By combining the First and Last name columns, the FullName calculated column may be formed.
CHECK: The CHECK constraint is used to limit the set of alternative values for a column. When a CHECK constraint is applied to a single column, only certain values are permitted. The CHECK constraint in a table might constrain the values in some columns based on the values in other columns in the row. The following SQL creates a CHECK constraint on the “Age” field when the “Persons” table is created. The CHECK limitation prevents anyone under the age of 18 from entering.
ORDER BY: Sorting the result set by one or more of the SELECT section’s items is possible with ORDER BY. Although ascending (ASC) is the usual sort order, you can use DESC to sort in the opposite direction (descending).
HAVING: HAVING allows you to filter the data acquired by the GROUP BY clause so that just a subset of the records is visible to the user.
COUNT: COUNT counts the number of rows in the result set and displays it as a column. COUNT can be used in a variety of ways, as shown below:
Counting all of the rows in a table (no group by required)
Counting the sums of subsets of data (needs a Group) (According to the portions of the statement)
This SQL statement returns the total number of rows. You can give the produced COUNT column a name by using “AS.”
Final Thoughts: The list above highlights the best commands used in SQL. If you want to learn more commands, remember that the internet is full of free resources. I’d recommend Youtube. It is the best place to learn it. If you need tutorials, you can always look them up on YouTube. You may find a number of SQL tutorials on YouTube. The only issue with YouTube is that it is difficult to learn new things quickly. The videos are not organized in any way.
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