Oracle 5.0 Reference Manual page 1107

HIGH_PRIORITY
•
STRAIGHT_JOIN
clause. You can use this to speed up a query if the optimizer joins the tables in nonoptimal
FROM
order.
STRAIGHT_JOIN
"JOIN Syntax".
STRAIGHT_JOIN
[646]
system
query execution, and references to its columns are replaced with the appropriate column values
before query execution proceeds. These tables will appear first in the query plan displayed by
EXPLAIN. See
[646]
const
(that is, the right-side table of a
•
SQL_BIG_RESULT
optimizer that the result set has many rows or is small, respectively. For SQL_BIG_RESULT, MySQL
directly uses disk-based temporary tables if needed, and prefers sorting to using a temporary table
with a key on the
tables to store the resulting table instead of using sorting. This should not normally be needed.
•
SQL_BUFFER_RESULT
the table locks early and helps in cases where it takes a long time to send the result set to the
client. This option can be used only for top-level
UNION.
•
SQL_CALC_FOUND_ROWS
set, disregarding any
FOUND_ROWS(). See
• The
SQL_CACHE
(see Section 8.6.3, "The MySQL Query
query cache if it is cacheable and the value of the
or DEMAND. With SQL_NO_CACHE, the server does not use the query cache. It neither checks the
query cache to see whether the result is already cached, nor does it cache the query result. (Due to
a limitation in the parser, a space character must precede and follow the
nonspace such as a newline causes the server to check the query cache to see whether the result is
already cached.)
For a query that uses UNION, subqueries, or views, the following rules apply:
•
SQL_NO_CACHE
• For a cacheable query,
first
SELECT
13.2.8.1.
SELECT ... INTO
The
SELECT ... INTO
file:
•
SELECT ... INTO var_list
•
SELECT ... INTO OUTFILE
specified to produce a specific output format.
•
SELECT ... INTO DUMPFILE
The
SELECT
the end of the statement. It is also possible to use
cannot be used with
forces the optimizer to join the tables in the order in which they are listed in the
also can be used in the
does not apply to any table that the optimizer treats as a
table. Such a table produces a single row, is read during the optimization phase of
Section 8.2.1, "Optimizing Queries with
or [646] tables that are used on the NULL-complemented side of an outer join
system
LEFT JOIN
or
SQL_SMALL_RESULT
elements. For SQL_SMALL_RESULT, MySQL uses fast temporary
GROUP BY
forces the result to be put into a temporary table. This helps MySQL free
tells MySQL to calculate how many rows there would be in the result
clause. The number of rows can then be retrieved with
LIMIT
Section 12.13, "Information
and
SQL_NO_CACHE
applies if it appears in any
SQL_CACHE
of a view referred to by the query.
Syntax
form of
SELECT
selects column values and into variables.
writes the selected rows to a file. Column and line terminators can be
writes a single row to a file without any formatting.
syntax description (see
Syntax
SELECT
statements that are part of a UNION.
SELECT
table_references
EXPLAIN". This exception may not apply to
or the left-side table of a
can be used with
statements, not for subqueries or following
SELECT
Functions".
options affect caching of query results in the query cache
Cache").
SQL_CACHE
query_cache_type
in the query.
SELECT
applies if it appears in the first
enables a query result to be stored in variables or written to a
Section 13.2.8, "SELECT
immediately following the
INTO
1087
list. See Section 13.2.8.2,
const
RIGHT JOIN.
or
GROUP BY DISTINCT
tells MySQL to store the result in the
[485] system variable is
SQL_NO_CACHE
of the query, or in the
SELECT
Syntax") shows the
INTO
select_expr
[646] or
to tell the
SELECT
2
keyword; a
clause near
list.