PDF (US Ltr)
- 35.1Mb
PDF (A4)
- 35.2Mb
Man Pages (TGZ)
- 256.4Kb
Man Pages (Zip)
- 361.3Kb
Info (Gzip)
- 3.4Mb
Info (Zip)
- 3.4Mb
Search Results
https://dev.mysql.com/doc/refman/5.7/en/innodb-memcached-porting-mysql.html
SELECT CAST(c2 as unsigned integer) FROM demo_test; # Since there could be numeric values of 0, can't disqualify them. SELECT AVG(cast(c2 as unsigned integer)) FROM demo_test WHERE c2 BETWEEN '0' and '9999999999'; # Views let you hide the complexity ... Consider these aspects of memcached applications when adapting an existing MySQL schema or application to use the daemon_memcached plugin: memcached keys cannot contain spaces or newlines, because these characters are used as separators in the ASCII ...
https://dev.mysql.com/doc/refman/5.7/en/innodb-persistent-stats.html
You can check the accuracy of statistics by comparing the actual cardinality of an index (determined by running SELECT DISTINCT on the index columns) with the estimates in the mysql.innodb_index_stats table. row *************************** ... The ...
https://dev.mysql.com/doc/refman/5.7/en/locking-service.html
To acquire one or more read locks, call this function: mysql> SELECT service_get_read_locks('mynamespace', 'rlock1', 'rlock2', 10); +---------------------------------------------------------------+ | service_get_read_locks('mynamespace', 'rlock1', ... MySQL distributions provide a locking interface that is accessible at two levels: At the SQL level, as a set of loadable functions that each map onto calls to the service ...
https://dev.mysql.com/doc/refman/5.7/en/mysql-cluster-replication-conflict-resolution.html
Like logging method selection, it is enabled by entries in the mysql.ndb_replication table. +------+--------+------+ mysql> SELECT id, name, members FROM department; +-----+-------------+---------+ | id | name | members | ... Requirements Source ...
https://dev.mysql.com/doc/refman/5.7/en/nested-join-optimization.html
Suppose that a join query over 3 tables T1,T2,T3 has this form: SELECT * FROM T1 INNER JOIN T2 ON P1(T1,T2) INNER JOIN T3 ON P2(T2,T3) WHERE P(T1,T2,T3) Here, P1(T1,T2) and P2(T3,T3) are some join conditions (on expressions), whereas P(T1,T2,T3) is ...The following discussion refers to the join syntax described in Section 13.2.9.2, “JOIN ...
https://dev.mysql.com/doc/refman/5.7/en/performance-schema-quick-start.html
If this engine is available (which you should already have checked earlier), you should see it listed with a SUPPORT value of YES in the output from the Information Schema ENGINES table or the SHOW ENGINES statement: mysql> SELECT * FROM ... This ...
https://dev.mysql.com/doc/refman/5.7/en/range-optimization.html
To work around this limitation, you can use a UNION with identical SELECT statements, except that you put each spatial predicate in a different SELECT. Range Optimization of Row Constructor Expressions The optimizer is able to apply the range scan ... The range access method uses a single index to retrieve a subset of table rows that are contained within one or several index value ...
https://dev.mysql.com/doc/refman/5.7/en/semijoins.html
To list the classes that actually have students enrolled, you could use this join: SELECT class.class_num, class.class_name FROM class INNER JOIN roster WHERE class.class_num = roster.class_num; However, the result lists each class once for each ...
https://dev.mysql.com/doc/refman/5.7/en/string-literals.html
These statements are equivalent: SELECT N'some text'; SELECT n'some text'; SELECT _utf8'some text'; For information about these forms of string syntax, see Section 10.3.7, “The National Character Set”, and Section 10.3.8, “Character Set ... A ...
https://dev.mysql.com/doc/refman/5.7/en/subquery-materialization.html
(oe_1, oe_2, ..., oe_N) [NOT] IN (SELECT ie_1, i_2, ..., ie_N ...) The predicate has this form, when there is a single outer expression oe and inner expression ie. oe [NOT] IN (SELECT ie ...) The predicate is IN or NOT IN and a result of UNKNOWN ...