SQL SELECT

Internal

• SQL
• SQL WHERE

Overview

A query consists in at least one (SELECT) and at most six categories of clauses

SELECT FROM WHERE GROUP BY HAVING ORDER BY 

Upon execution, an SQL query returns a result set.

Query execution. SQL optimizer. Subqueries.

Select all (possibly across multiple tables) then filter and discard with where.

Example

SELECT id, name FROM person WHERE id = 1;

Clauses

FROM

FROM permanent|derived|temporary|virtual(view)

Table alias.

Querying Multiple Tables

Querying Multiple Tables

WHERE

The WHERE Clause

GROUP BY ... HAVING

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