Limit immer angeben, zwecks Speed ?

[CannabisCow]

Also jetzt mal wieder so ne Speed - Frage

Sollte man ein Limit immer angeben ?

Bsp: SELECT event FROM tabelle WHERE date = '24.12.2002'

Nehmen wir an es gibt nur einen Event, der zutrifft.
Wäre es dann ratsam ein Limt anzugeben damit er gleich weiss das es nur einen Datensatz gibt, denn sonst würde er ja weitersuchen, wenn er Datensatz fndet, oder ?

[TBT]

definitiv JA

von der mysql Seite:

- If you are selecting only a few rows with LIMIT, MySQL will use indexes in some cases when it normally would prefer to do a full table scan.
- If you use LIMIT # with ORDER BY, MySQL will end the sorting as soon as it has found the first # lines instead of sorting the whole table.
- When combining LIMIT # with DISTINCT, MySQL will stop as soon as it finds # unique rows.
- In some cases a GROUP BY can be resolved by reading the key in order (or do a sort on the key) and then calculate summaries until the key value changes. In this case LIMIT # will not calculate any unnecessary GROUP BYs.
- As soon as MySQL has sent the first # rows to the client, it will abort the query (if you are not using SQL_CALC_FOUND_ROWS).
LIMIT 0 will always quickly return an empty set. This is useful to check the query and to get the column types of the result columns.
- When the server uses temporary tables to resolve the query, the LIMIT # is used to calculate how much space is required.

[CannabisCow]

Da sag ich doch: DANKE