June 27, 2008 01:26AM Re: select query not using indexes 2222 Rick James June 27, 2008 11:23PM Re: select query not using indexes 1947 Alon Lubin June 18, 2008 08:22AM Sorry, you can't reply to this topic. It has been closed....
RENAME USER 'admin'@'%' TO 'admin'@'172.16.1.108'; (8)、给用户加密码 第一种:SET PASSWORD FOR 'USERNAME'@'HOST'=PASSWORD('NEW_PASSWORD'); mysql> SET PASSWORD FOR 'root'@'localhost'=PASSWORD('redhat'); Query OK, 0 rows affected (0.03 sec) 第二种:mysqladmin -uUSERNAME -hHOST ...
"expanded_query":"/* select#1 */ select `test03`.`id` AS `id`,`test03`.`dept` AS `dept`,`test03`.`name` AS `name`,`test03`.`create_time` AS `create_time`,`test03`.`last_login_time` AS `last_login_time` from `test03` whe...
If part or all of the result of aSELECTstatement is equivalent to an existing materialized view, then Oracle Database may use the materialized view in place of one or more tables specified in theSELECTstatement. This substitution is calledquery rewrite. It takes place only if cost optimization ...
"SELECT INTO" with indexes? "Simple" SQL to check for alpha or numeric charcters isn't working right "String or binary data would be truncated.\r\nThe statement has been terminated." "String or binary data would be truncated" and field specifications “Unable to enlist in the transaction”...
It takes place only if cost optimization is enabled and the QUERY_REWRITE_ENABLED parameter is set to TRUE. To determine whether query rewrite has occurred, use the EXPLAIN PLAN statement. See Also: SQL Queries and Subqueries for general information on queries and subqueries Oracle Database ...
MySQL sometimes optimizes a query that has a LIMIT row_count clause and no HAVING clause: • If you select only a few rows with LIMIT, MySQL uses indexes in some cases when normally it would prefer to do a full table scan. • If you combine LIMIT row_count with ORDER BY, MySQL ...
If so, create an appropriate index and check the query with EXPLAIN again. See Section 6.5.4. To see what indexes a table has, use SHOW INDEX FROM tbl_name. key The key column indicates the key (index) that MySQL actually decided to use. The key is NULL if no index was chosen. ...
You need to ensure you avoid full-table scans, particularly if you’re dealing with large tables of data. This creates unnecessary input/output and can slow everything down. Look at the number of rows you’re requesting with the query and use indexes to break your results down into smaller...
1. A portion of ranges, possibly single-key ranges, is accumulated in a buffer on the central node where the query is submitted. 2. The ranges are sent to the execution nodes that access data rows. 3. The accessed rows are packed into packages and sent back to the central node. ...