Difference between SQL and PL/SQL

Ashok Kumar - 16 February 2022 - 0 Comments
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Difference between SQL and PL/SQL

The main difference between SQL and PLSQL is that SQL is a query language used to store, manipulate, and retrieve data in a relational database, while PLSQL is an extension of SQL used to manage data in the Oracle Relational Database.

A relational database management system stores data in databases. A database consists of a collection of tables. SQL allows users to access RDBMS data. It also describes the type of data stored in the database. On the other hand, PLSQL is an extension of SQL. Its specific use is data management in the Oracle Relational database. SQL executes only one statement at a time, while PLSQL executes one block of statements at a time. In short, SQL refers to the general query language while PLSQL refers to the query language specifically used for Oracle databases.

SQL and PL/SQL are relational database languages. SQL is a structured query language that adds, deletes, modifies, or manipulates data in the database. PL/SQL is a procedural language that is an extension of SQL and contains SQL statements in its syntax. The fundamental difference between SQL and PL/SQL is that only one query is executed at a time in SQL, whereas in PL/SQL, an entire block of code is executed at a time.

Let us discuss a few other differences between SQL and PL/SQL using the comparison table presented below.

Comparison table
It is a structured database query language. It is a database programming language using SQL.
Data variables are not allowed Data variables are allowed.
No control structure supported. Control structures are supported e.g. the for, while, etc. loop.
The query performs a single operation. The PL/SQL block executes the operation group as a single block.
SQL is a declarative language. PL/SQL is a procedural language.
SQL can be integrated with PL/SQL. PL/SQL can be embedded in SQL.
It interacts directly with the database server Does not interact with the database server.
It is a data-driven language. It is an application-oriented language.
It is used to write queries, DDL, and DML statements. These are program blocks, functions, procedure triggers, and packages.

Defining SQL

SQL (Structured Query Language) is a relational database language established and developed by IBM in 1970. It defines the set of relationships (tables) in the database using DDL, which is the data definition language. DDL is used to create the schema of each relationship and maintains the integrity constraints, security, and authorization of each relationship.

The other part of SQL is DML, which is the data manipulation language. DML allows a user to access or manipulate data in the database. DMLs are essential of two types: procedural DML and declarative or non-procedural DML. Procedural DML statements specify what data is required and how to recover that data. On the other hand, the declarative DML statement specifies only the necessary data. SQL uses declarative DML.

SQL can be integrated with the syntax of many other languages such as C/C++, Java, Perl, Python, PHP, etc. It is a data-driven declarative language.


Commands such as CREATE, ALTER, and DROP belong to DDL. The CREATE command is used to create databases and tables. ALTER allows you to modify tables while DROP is used to delete a table, view, or another database object.


Commands such as SELECT, INSERT, UPDATE, and DELETE are categorized as DML. The SELECT command is used to select a set of records from the table. INSERT is used to enter a new record in the table. UPDATE is used to modify an existing record, while DELETE is used to delete a certain record.


Commands such as GRANT and INVOKE belong to DCL. GRANT is used to give a privilege to a user, while REVOKE is used to retrieve the privilege granted to the user. These are the main types of SQL commands.

Definition of PL / SQL

PL/SQL is a procedural relational database language developed by Oracle Corporation in the early 90s. PL/SQL is the language used by Oracle along with the other two languages SQL and Java. It is an extension of SQL and incorporates SQL statements into its syntax.

PL/SQL allows a block of code to run at a time that increases its performance. The code block is composed of procedures, functions, loops, variable packages, triggers. PL/SQL is designed to create web applications and server pages. PL/SQL inhibits features such as encapsulation, data masking, exception handling, and object-oriented data type.

PLSQL provides programming structures such as conditions, loops, and arrays. A subprogram is a unit that performs a specific task. PLSQL has two types of subprograms. These are functions and procedures. A function is used to calculate and return a value. A procedure is used to perform an action. It does not return a value directly.

An exception is a condition that interrupts the normal flow of execution. PLSQL allows users to handle exceptions. In addition, a trigger is a registered program that is executed automatically when an event occurs. It is possible to write triggers using PLSQL. Here are some advantages of using PLSQL.

Key differences between PL/SQL and SQL 

  1. The fundamental difference between the two languages is that SQL executes the single query at once, while Pl/SQL executes the block of code at once.
  2. SQL is a structured query language while PL/SQL is a structured procedure language/query language.
  3. SQL acts as a source to retrieve the data that will be displayed by the application created using PL/SQL.
  4. SQL queries and commands are written using Data Definition Language (DDL) and Data Manipulation Language (DML). However, using PL/SQL, you can write a programming block containing procedures, functions, triggers, packages, and variables.
  5. SQL queries are used to retrieve data from the database. You can also add, remove, or modify data in the database. On the other hand, PL/SQL is used to create applications that can display the information retrieved by the SQL.
  6. You can embed SQL queries in pl/SQL syntax. However, the reverse is not possible.

Long shape

The structured query language is the long-form of SQL while the procedural extension language for SQL is the long-form of SQL.

Executing the command

While SQL executes only one command or query at a time, PLSQL executes one block of code at a time. This is another difference between SQL and PLSQL.

Consist of

SQL does not contain PLSQL. PLSQL is an extension of SQL. Therefore, PLSQL can contain SQL.


SQL queries can be written using the DDL, DML, and DCL commands. It is possible to write PLSQL code using functions, procedures, triggers, variables, etc.

Primary use

Usage is another important difference between SQL and PLSQL. SQL is mainly used to select and manipulate datasets while PLSQL is used for web applications and server pages.


The difference between SQL and PLSQL is that SQL is a query language used to store, manipulate, and retrieve data in a relational database, while PLSQL is an extension of SQL used to manage data in Oracle Relational Database. It is possible to integrate SQL into PLSQL because it is an extension of SQL.

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