SQL
データに何でも聞ける言語。
SQL is the language of databases. Every post, like and game score in an app like Nova lives in database tables, and SQL is how you ask those tables questions. This track starts from zero: reading tables with SELECT, filtering and sorting, counting and grouping, joining tables, changing data safely, designing your own tables, and finally subqueries, CTEs and window functions.
Every lesson works with the same small dataset from Nova, a made-up social app (users, posts, likes and scores) and shows the exact result of every query, so you always know what answer to expect.
- レッスン
- 25
- 時間
- 3 時間
- レベル
- 初級
このコースのレッスンは、現在英語のみです。
- ブロンズ 挑戦可
- シルバー 挑戦可
- ゴールド ロック
実力を証明しますか？
ブロンズ、シルバー、ゴールドの 3 つの試験が待っています。
できるようになること
- Read and filter any table with SELECT and WHERE
- Summarize data with COUNT, SUM, AVG, GROUP BY and HAVING
- Combine tables with INNER JOIN and LEFT JOIN
- Insert, update and delete rows safely inside transactions
- Design tables with keys, constraints and indexes
- Build a leaderboard with subqueries, CTEs and window functions
学習の道のり
1 第 1 章Databases and tables
What a relational database is, how tables are built, and your first SELECT.
0 / 32 第 2 章Filtering and sorting
Keep only the rows you want, handle NULL correctly and put results in order.
0 / 43 第 3 章Aggregation
Turn many rows into answers: counts, totals, averages and groups.
0 / 34 第 4 章Joins
Combine tables: match rows, keep the unmatched ones and find what is missing.
0 / 35 第 5 章Changing data
Add, change and remove rows, and use transactions so mistakes can be undone.
0 / 46 第 6 章Designing tables
Create tables with the right types, protect them with constraints and speed them up with indexes.
0 / 47 第 7 章Powerful queries
Subqueries, EXISTS, CTEs, CASE and window functions for real leaderboards.
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