SQL SELECT: Difference between revisions
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A query consists in at least one (<code>[[#SELECT|SELECT]]</code>) and at most six categories of [[#Clauses|clauses]]: | A query consists in at least one (<code>[[#SELECT|SELECT]]</code>) and at most six categories of [[#Clauses|clauses]]: | ||
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[[#SELECT|SELECT]] [...] FROM [...] WHERE [...] GROUP BY [...] HAVING [...] ORDER BY [...] | [[#SELECT|SELECT]] [...] [[#FROM|FROM]] [...] [[#WHERE|WHERE]] [...] GROUP BY [...] HAVING [...] ORDER BY [...] | ||
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Revision as of 23:13, 22 May 2024
Internal
Overview
A query consists in at least one (SELECT) and at most six categories of clauses:
SELECT [...] FROM [...] WHERE [...] GROUP BY [...] HAVING [...] ORDER BY [...]
The following query:
SELECT;
is valid, it returns one empty row.
Upon execution, an SQL query returns a result set.
Select all (possibly across multiple tables) then filter and discard with where.
Example
SELECT id, name FROM person WHERE id = 1;
Clauses
SELECT
FROM
FROM permanent|derived|temporary|virtual(view)
Table alias.
Querying Multiple Tables
WHERE
GROUP BY ... HAVING
(make sure I understand thoroughly and link)