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Free module

Databases at work

Databases at work: designing tables, SELECT and WHERE, sorting and grouping, joins and transactions, in plain SQL.

6 lessons280 min lesson

The lessons

Each lesson is free to read in full. Create a free account to run its commands in a live lab and to sit its quizzes and tasks.

  1. 1

    Find the rows that match

    I can use SQL to find the rows that match a condition.

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  2. 2

    Count and total in groups

    I can count and total rows in groups with SQL.

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  3. 3

    Join two tables for one answer

    I can join two tables to answer one question.

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  4. 4

    Why an index makes a query fast

    I can explain how an index makes a query faster.

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  5. 5

    All or nothing with transactions

    I can explain why a transfer must be all or nothing.

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  6. 6

    Store each fact only once

    I can split data into tables so each fact is stored once.

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