SQL Query Writing for Beginners

Meet the team behind Cinderella's relational database, learn how Cathy designs tables, Ingur inserts data, and Manny updates, while Penny builds a web app to run sql queries.

Cathy creator guides you in designing database tables and building the Cinderella schema. Explore relationships among subjects, parties, photos, behavior data, and data types for SQL.

Learn to design tables in a Cinderella 1 schema by defining columns with text, number, and date data types, then write create table statements to build your database.

Learn database normalization through the Cinderella schema, focusing on three rules: no repeating columns, single attribute per row, and topic-specific tables. See how separating subjects and parties reduces duplicates.

discover how primary keys uniquely identify rows and how foreign keys link related tables to normalize relational databases, illustrated with subjects, parties, and behavior data.

Learn to insert, update, and delete data in a sql database using insert into, values, update, and delete statements, with practical examples from Inga and Manny.

Learn to write SQL queries to retrieve data from a relational database using select and from clauses, view results, and understand returning columns, rows, and full-table selections.

Discover how a web app built on a relational database uses SQL to display user data, profiles, photos, and memories, with authentication and security roles.

Learn beginner-friendly SQL query writing for data entry tasks, covering core concepts to efficiently query and manage data in relational databases.

Learn to use the query tool to write sql queries, run them on the database, and print or save results in the catalog for sharing with others.

Learn to use the where clause to filter query results with equal and not equal operators, including text vs numeric comparisons, and place the where clause after select and from.

Master sql query writing for beginners using where clauses and operators like less than, greater than, and equal to to filter party scores and 18 or over on party date.

Learn to write SQL queries with multiple conditions by using and and or in the where clause, filtering by age (18+), active status, and marital status.

Learn to use like, not like, in, is null, is not, and not in operators in the where clause for multiple conditions and a certain pattern of characters in SQL.

Learn how to use the sum function in SQL queries to total amounts from the party costs table, including filtering by the current month and preparing totals for reporting.

Learn how to use the group by clause with the sum function to aggregate totals by category, such as party id or cost type, and reduce manual calculations.

Learn how to apply aggregate functions in sql queries, such as count, average, max, and min, with group by to analyze party scores.

Master SQL query writing for beginners by using constants and calculated columns in the select clause, including static values, arithmetic operations, and concatenating fields.

Learn how aliasing renames columns and tables to create clear headers, and how to use order by to sort results for easy reading, including multiple columns and descending order.

Discover how the distinct keyword after select removes duplicate rows in a query. See examples with cost types and subject history that use effective dates and updates.

Master inner joins to bring multiple tables together in a single SQL query, enabling data from different tables to appear in one report and reveal results after extraction.

Explore how to use a left outer join to return all rows from the first table and matched rows from the second, with nulls where there is no match.

Explore subqueries and their role in the where clause to power up your main queries, using examples like average and max behavior scores to filter subjects.