In Oracle, compare SQL and PL/SQL by explaining what each one is, how they differ in capabilities, and how they complement each other in real applications.

Introduction / Context:
SQL and PL/SQL appear together in almost every Oracle project, but they serve different roles. Interviewers often ask candidates to compare them to check that they understand where to use plain SQL and where PL/SQL is more appropriate. This question focuses on the conceptual differences and how the two technologies work together.

Given Data / Assumptions:

• The database platform is Oracle, with support for both SQL and PL/SQL.
• SQL is already known as the standard Structured Query Language for relational databases.
• PL/SQL is recognized as a procedural programming language integrated with Oracle.
• Applications may use both within the same system.

Concept / Approach:
SQL is declarative. You describe what data you want, not how to retrieve it, using statements like SELECT, INSERT, UPDATE, DELETE, CREATE, and ALTER. SQL lets the optimizer choose the best access path. PL/SQL is procedural. It adds programming constructs such as variables, loops, conditionals, subprograms, and exception handling. PL/SQL blocks can contain many SQL statements and control flow to implement business logic. SQL focuses on set based data operations, while PL/SQL orchestrates those operations over time in a block of logic.

Step-by-Step Solution:
Step 1: Explain that SQL defines and manipulates data structures in a relational model, including tables, indexes, and views.Step 2: Describe that SQL statements operate on sets of rows at once, which is ideal for aggregation, filtering, and joins.Step 3: State that PL/SQL is a programming language built around SQL that allows control flow, modular design, and error handling inside the database.Step 4: Show that PL/SQL blocks embed SQL statements, so PL/SQL depends on SQL for actual data manipulation.Step 5: Conclude that SQL and PL/SQL complement each other, with SQL doing set based data work and PL/SQL coordinating and extending that work, which is what option A captures.

Verification / Alternative check:
If you try to write a loop or declare a variable using only plain SQL, you immediately run into limitations because SQL does not provide general purpose programming constructs. Conversely, if you write PL/SQL without any SQL statements, you will not interact with data at all. Real applications use SQL for set operations and PL/SQL as glue code within the database.

Why Other Options Are Wrong:
Option B treats SQL and PL/SQL as identical, which is clearly false. Option C relegates PL/SQL to operating system tasks, ignoring its close integration with data. Option D misclassifies their roles and leaves out key capabilities such as querying and procedural logic.

Common Pitfalls:
A common mistake is writing row by row PL/SQL loops when a single set based SQL statement would be faster. Another is trying to force SQL to behave like a procedural language. Experienced developers choose SQL for pure data transformations and PL/SQL when they need conditional logic, loops, and robust error handling around those transformations.

Final Answer:
SQL is a declarative language used to define and query data sets, while PL/SQL is a procedural extension that adds variables, control structures, and modular code so that SQL statements can be grouped and executed with logic inside the database.