what are the commands in sql

^{Some of The Most Important SQL Commands}

• SELECT - extracts data from a database
• UPDATE - updates data in a database
• DELETE - deletes data from a database
• INSERT INTO - inserts new data into a database
• CREATE DATABASE - creates a new database
• ALTER DATABASE - modifies a database
• CREATE TABLE - creates a new table
ALTER TABLE - modifies a table
DROP TABLE - deletes a table
CREATE INDEX - creates an index (search key)
DROP INDEX - deletes an index

Full Answer

What are the basic commands of SQL?

What are the 5 basic SQL commands?

• Data Definition Language (DDL) DDL changes the structure of the table like creating a table, deleting a table, altering a table, etc. …
• Data Manipulation Language. …
• Data Control Language. …
• Transaction Control Language. …
• Data Query Language.

What are the DML, DDL, and Tcl commands in SQL?

What Are The DML, DDL, and TCL Commands in SQL?

• The Three Main Statement Types. Let’s take a look at each of these statement types.
• DDL – Data Definition Language. ...
• DML – Data Manipulation Language. ...
• TCL – Transaction Control Language. ...
• Session Control Statements. ...
• System Control Statements. ...

What are the basics of SQL?

SQL stands for Structured Query Language. SQL commands are the instructions used to communicate with a database to perform tasks, functions, and queries with data. SQL commands can be used to search the database and to do other functions like creating tables, adding data to tables, modifying data, and dropping

What are the syntax rules for SQL?

SELECT statements

1. SELECT command provides the query proficiency. It retrieves information and useful data from the table.
2. By executing SELECT command current information in the table will reflect on the screen.
3. The SELECT statement has three basic components that is: SELECT, FROM and WHERE
4. This command extract useful information and stored in a table. ...

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What are the 5 types of SQL commands?

Types of SQL CommandsDDL (Data Definition Language)DML (Data Manipulation Language)DQL (Data Query Language)DCL (Data Control Language)Data administration commands.Transactional control commands.

What are commands in SQL?

SQL commands are the instructions used to communicate with a database to perform tasks, functions, and queries with data. SQL commands can be used to search the database and to do other functions like creating tables, adding data to tables, modifying data, and dropping tables.

How many types of commands are there in SQL?

There are 3 main types of commands. DDL (Data Definition Language) commands, DML (Data Manipulation Language) commands, and DCL (Data Control Language) commands.

What are the four SQL commands?

The main types of commands present in SQL are:Data Definition Language (DDL)Data Manipulation Language (DML)Data Control Language (DCL)Transaction Control Language (TCL)Data Query Language (DQL)

What are DDL DML and DCL?

DDL – Data Definition Language. DQl – Data Query Language. DML – Data Manipulation Language. DCL – Data Control Language.

What is basic SQL?

THE BELAMY Structured Query Language (SQL) is a powerful database tool that is used to perform operations such as create, maintain and retrieve data stored in the relational database. It is basically a standard language for data manipulation in a Database Management System (DBMS).

How can I see all SQL commands?

List of SQL CommandsSELECT. SELECT is probably the most commonly-used SQL statement. ... SELECT * SELECT used with an asterisk (*) will return all of the columns in the table we're querying. ... SELECT DISTINCT. ... SELECT INTO. ... SELECT TOP. ... AS. ... FROM. ... WHERE.More items...•

What is DDL in SQL?

Data Definition Language (DDL) Statements Create, alter, and drop schema objects. Grant and revoke privileges and roles. Analyze information on a table, index, or cluster. Establish auditing options. Add comments to the data dictionary.

What is DDL and DML in SQL?

DDL is Data Definition Language which is used to define data structures. For example: create table, alter table are instructions in SQL. DML: DML is Data Manipulation Language which is used to manipulate data itself. For example: insert, update, delete are instructions in SQL.

What is SQL command list?

This is a SQL commands list that covers all the necessary actions with SQL databases. Each SQL command is provided with its definition, a code snippet that represents the correct syntax, and some have live code examples that you can try modifying to see the command in action.

What is AS in SQL?

AS allows you to rename a column or table to a more convenient alias (a correlation name) without changing the original names in the database. This makes writing queries easier when the original table or column names are long or complicated.

What is a view in SQL?

CREATE VIEW creates a narrower version of an existing table by getting a set of results based on a certain query. A view is not much different from a real table: it contains columns and rows with data, but it doesn't contain the fields of the real table that are irrelevant for your particular purpose.

What does "drop" mean in SQL?

DROP DATABASE is one of the riskiest statements that should be used with extra caution. In SQL, drop means delete – and DROP DATABASE deletes the whole specified database together with all its parameters and data.

What is SQL command?

SQL commands are the instructions used to communicate with a database to perform tasks, functions, and queries with data. SQL commands can be used to search the database and to do other functions like creating tables, adding data to tables, modifying data, and dropping tables. Here is a list of basic SQL commands (sometimes called clauses) ...

What is the select part of a query?

The SELECT part of a query determines which columns of the data to show in the results. There are also options you can apply to show data that is not a table column.

When to use like in SQL?

LIKE is used in a WHERE or HAVING (as part of the GROUP BY) to limit the selected rows to the items when a column has a certain pattern of characters contained in it. This SQL will select students that have FullName starting with “Monique” or ending with “Greene”.

What is a view in SQL?

A view in SQL is a single table, which is derived from other tables. So, a view contains rows and columns similar to a real table and has fields from one or more table.

What is the like operator in a table?

The LIKE operator is used in a WHERE clause to search for a specified pattern in a column of a table. There are mainly two wildcards that are used in conjunction with the LIKE operator:

What is a nested query?

Nested queries are those queries which have an outer query and inner subquery. So, basically, the subquery is a query which is nested within another query such as SELECT, INSERT, UPDATE or DELETE. Refer to the image below:

What is a candidate key?

Candidate Key – A set of attributes which can uniquely identify a table can be termed as a Candidate Key . A table can have more than one candidate key, and out of the chosen candidate keys, one key can be chosen as a Primary Key.

Is SQL a database?

Relational databases are one of the most popular databases, and SQL is the basis of relational databases. Therefore SQL skills are indispensable in most of the job roles. In this article on SQL Commands, I will discuss the top commands and statements that you need to understand in SQL.

BETWEEN

The BETWEEN operator is used to filter the result set within a certain range. The values can be numbers, text or dates.

CASE

CASE statements are used to create different outputs (usually in the SELECT statement). It is SQL’s way of handling if-then logic.

COUNT ()

COUNT () is a function that takes the name of a column as an argument and counts the number of rows where the column is not NULL.

CREATE TABLE

CREATE TABLE creates a new table in the database. It allows you to specify the name of the table and the name of each column in the table.

GROUP BY

GROUP BY is a clause in SQL that is only used with aggregate functions. It is used in collaboration with the SELECT statement to arrange identical data into groups.

HAVING

HAVING was added to SQL because the WHERE keyword could not be used with aggregate functions.

INNER JOIN

An inner join will combine rows from different tables if the join condition is true.

What is SQL command?

SQL commands are instructions. It is used to communicate with the database. It is also used to perform specific tasks, functions, and queries of data. SQL can perform various tasks like create a table, add data to tables, drop the table, modify the table, set permission for users.

What are the different types of SQL commands?

Types of SQL Commands. There are five types of SQL commands: DDL, DML, DCL, TCL, and DQL. 1. Data Definition Language (DDL) DDL changes the structure of the table like creating a table, deleting a table, altering a table, etc. All the command of DDL are auto-committed that means it permanently save all the changes in the database.

What commands can be used with TCL?

TCL commands can only use with DML commands like INSERT, DELETE and UPDATE only. These operations are automatically committed in the database that's why they cannot be used while creating tables or dropping them. Here are some commands that come under TCL: COMMIT.

Database Tables

A database most often contains one or more tables. Each table is identified by a name (e.g. "Customers" or "Orders"). Tables contain records (rows) with data.

SQL Statements

Most of the actions you need to perform on a database are done with SQL statements.

Semicolon after SQL Statements?

Some database systems require a semicolon at the end of each SQL statement.

WHERE Clause Example

The following SQL statement selects all the customers from the country "Mexico", in the "Customers" table:

Text Fields vs. Numeric Fields

SQL requires single quotes around text values (most database systems will also allow double quotes).