Oracle SQL - A Complete Introduction

Download and install Oracle Database Express Edition on Windows, noting that Mac is not supported. Establish a SQL Developer connection using localhost, port 1521, and the pluggable database service name.

Learn how to use the between and not between keywords in Oracle SQL to filter records by a range, including hires in 2016 and IDs between 10 and 20.

Explore the any keyword in Oracle SQL, comparing salaries against list values using all, any, greater than, less than, and not equals with practical examples.

Master ordering by multiple columns using the order by clause, sorting by last name then first name, with individual ascending or descending orders for date and employee id.

combine results from two queries with the union operator in oracle sql, ensuring matching columns and label records as employee or customer, then order the final set by name.

Compare union and union all to learn how duplicates are handled when combining two queries. Use union all to preserve duplicates and improve performance when removing duplicates isn't needed.

Learn how the intersect operator returns only records that exist in both queries, contrasting with union and union all; practical examples show shared values like 2 and 4.

Explain how the minus operator excludes data from query one that exists in query two, using examples of union, union all, and intersect in Oracle SQL.

Discover how to count records in Oracle SQL using count(*), count(1), and where clauses to determine table sizes and data occurrences.

Master grouping with the group by clause and count in Oracle SQL, counting value occurrences and applying where and order by after grouping.

Learn how to use group by with where and order by in Oracle SQL to filter data before counting. Use like operator with wildcards and sort results by count.

Learn how to use group by with multiple columns in SQL to count occurrences, display values, and order results by count or by named columns.

Learn to filter groups with having after a group by in Oracle SQL, and why where cannot filter aggregates; count duplicates by last name and apply having.

Explore how the sum function adds numbers and works like count, including its use with group by. See examples summing salaries and product prices to reveal department totals.

Learn how the AVG function computes the average from numbers and that it only accepts numeric values, with examples like department salary averages grouped and ordered by the mean.

Learn how table and column aliases shorten queries, improve readability, and simplify joins in Oracle SQL, with practical examples using an employee table.

Learn how to rename query result columns with column aliases to improve readability and reporting, using optional as, double quotes for spaces, with examples like annual and monthly salary.

Discover how joins link two or more tables in a single query using a common value, enabling you to fetch employee and department data.

Learn how inner join links two tables on a common value to display only matching records from both tables, using from, join, and on, with qualifiers and aliases.

Learn how left outer join returns all records from the left table with matching or null values from the right, illustrated with customers and orders and with departments and employees.

Learn the full outer join, which combines left and right joins to return all records from both tables and shows nulls where no matches exist, using full join syntax.

Learn how natural joins automatically join on columns with the same name, see examples with employee and department tables, and understand why explicit joins are preferred for maintainability and correctness.

Learn how cartesian (cross) joins create a cartesian product by joining every record from one table to every record in another and why join conditions matter.

Explore Oracle's alternative join syntax and compare it with the ANSI standard, learn why join conditions belong in the from clause, and avoid accidental Cartesian joins.

Learn how to nest string functions inside other functions in Oracle SQL, extracting email domains by combining length, position, and substring, with dynamic lengths and clear column aliases.

Explore number functions in Oracle SQL, including round, ceiling, floor, and rand; learn rounding to whole numbers and decimals, then apply a 15% discount and price calculations.

Explore oracle date functions, including add months and months between, using current date and employee data to calculate probation review dates and five-year anniversaries.

Explore Oracle data types, including char and varchar2, number, date, timestamp, and clob, and learn how to convert between them using to_char, to_date, and to_number with practical examples.

Learn how the case statement enables conditional logic in SQL queries, using when, then, and else, with examples classifying prices into groups and grouping regions by address stage.