SQL For Beginners

Explore Oracle database data types, including fixed-length char, variable-length varchar2, and number and date types, and learn how domains define attribute values and memory efficiency.

Create table in sql: master the basic syntax to define a table with column names and data types, separate columns with commas, and end with a semicolon.

Learn how to apply constraints in SQL tables, including unique constraints on roll numbers to prevent duplicates, not null to require values, and check constraints to enforce age ranges.

Identify and enforce unique rows with primary key constraints, using columns like roll number or employee IDs, and relate tables with foreign keys to form customer–product relationships.

Learn how to alter tables in SQL by adding and dropping constraints, adding new columns, and modifying column data types with alter statements, including unique constraint handling.

Learn to use Oracle Live SQL in a browser-based worksheet to create a table, manage reserved keywords, and debug errors when a table already exists.

Learn how to use the insert into statement to add data into a table with the values keyword, including optional column lists and single or multiple row inserts.

Master the select statement in SQL to retrieve data from a table by listing specific columns or using the asterisk, and view results like name and age.

Learn how the select distinct keyword returns only unique values when querying a column. See how selecting distinct roll number from the student table yields unique roll numbers, avoiding duplicates.

Learn how to filter data with the SQL where clause by applying conditions using operators like equals, greater than, less than, and between to select specific rows.

Practice SQL queries on an employee table, filtering by country and identifying managers by position. Learn to use in and not in conditions to list employees by country.

Explain how to use the order by clause to sort SQL query results by one or more columns, with default ascending, optional descending, and tie-breaking by subsequent columns.

Master the update statement to modify specific rows using set and where with a condition, and avoid updating all rows in a table.

Learn how SQL aggregate functions take a collection of column values and return a single output, including min, max, sum, count, and average, by selecting from a table.

Explore pattern matching with the like operator in SQL by using wildcards, specifically the percent sign and underscore, to search for a pattern with zero, one, or multiple characters.

Explore pattern matching in sql with starts with, second letter, ends with, and has patterns on student names, using underscore and percent.

Master the sql group by statement to group data by a column and apply aggregate functions like count, average, max, and min, with students by country and employees by department.

Learn how to use the having clause to apply aggregate functions in SQL queries, unlike where which disallows aggregates, as illustrated by selecting students with the maximum score.

Learn to use the having clause alongside a where clause in SQL to filter grouped data by country, counting employees and displaying countries with more than 10 staff.

Master the basics of joins in sql by learning inner, left, right, full, and self joins, using customer and product tables to illustrate how related columns merge data.

Learn how inner join in SQL combines two tables by matching a common attribute, using an on condition to return rows with matching values.

Explore the left join in SQL, which returns all rows from the left table with matching right rows or nulls when no match, plus the on-syntax example.

Explore right join in SQL, which includes all rows from the right table and the matching rows from the left table, with nulls shown where there is no match.

Master how a full outer join combines two tables, including all rows and filling nonmatching values with nulls, illustrated with examples and a customer table analogy.

Learn to write subqueries and nested queries by embedding a select inside another select, and filter customers who bought a specific product using the customer and product tables.

Develop SQL queries on the world table to select name, continent, and population; compute per capita GDP; filter by population thresholds, continent filters, and pattern matching with LIKE.

Learn how window functions in SQL use partition by and over to compute per-employee totals from a sales table, applying sum and other aggregates.

Demonstrates SQL window functions with sum and max over partitions to compute item totals, using orders, and shows how partition by order_id avoids duplicates.