count from

Thinking about orcle 11g select count (*) from v $ lock, orcle11g recently, we found that the query by orcle 11g select count (*) from v $ lock is very slow, and I think it is necessary to perform a detailed analysis: select count(*) from v$lock;--

Mysql's count query efficiency from innodb to MyIsam has greatly improved recently, after the company has a business log table that exceeds 5 million, count (*) needs to be 4 minutes 55 seconds, after the storage engine of the table is converted

0 reply content: two links are provided: 1. Why does the indexing start with zero in 'C '? Http://stackoverflow.com/questions/7320686/why-does-the-indexing-start-with-zero-in-c ) 2. Why numbering shoshould start at zero, by Dijkstra.

Php Chinese network (www.php.cn) provides the most comprehensive basic tutorial on programming technology, introducing HTML, CSS, Javascript, Python, Java, Ruby, C, PHP, basic knowledge of MySQL and other programming languages. At the same time,

As shown in the following table: Table-----------------------------------Filed0 filed1-----------------------------------A 1A 2A 2B 2B 3B 3------------------------------------Run: Select filed0, count (*) from table where filed1> 2 group by

PHP Query Statement SELECT COUNT (*) from table where type= ' literary life '; How to output a result $sql = "SELECT count (*) from table where type= ' literary life '; $result =mysql_query ($sql); while ($row =mysql_fetch_array ($result)) { ?> ?

First, the program implementation process diagram:Second, the code implementation:OnePublic static void Main (string[] args) { int beernumber=;String beername="Bottles"; While (beernumber100) {System.out.println (beernumber+":"

Joseph Ring Problem: There are n individuals in a circle, numbered sequentially. Starting from the 1th person count (from 1-m count), where the people who report m out of the circle, ask the last left is the original number of that. "C Program

The problem stems from a problem with the python-CN Mail List: http://groups.google.it/group/python-cn/browse_thread/thread/758891b4342eb2d9/92c12bf6acd667ac Interestingly, why is the result of SYS. getrefcount (11111111) in python2.4 2, but

1, to determine the type of injection (digital or character) Character and digital data judgments: (I hope someone can further refine, subdivided into digital and character-type judgments in two parts) and User>char (0) and user

It takes only 6 minutes to scan a 166G table from an oracle full table, and oracle166g How can I maximize the cpu usage? How to quickly scan a large table. If a large table has a primary key, count (*) takes the primary key. oracle only needs to

Tag:sql    optimization    oracle    execution Plan     database      How to limit CPU utilization? How to scan the big table most quickly. If the large table has a primary key, COUNT (*) will go to the primary key, and Oracle only needs to scan the

* * The test is for the next test, according to the condition of the increment column as the partitioning condition, according to the time as the partition condition. Create tablespace test01 datafile ' D:\oracle\oradata\myora\test01.dbf ' size

* ** Injection basics ** (mainly manual and basic ~ Haha) Instance: http://www.XXX.com/jiaren.asp? ID = 544 Okay. Now we start ..... 1. Judgment Use;Use and 1 = 1 and 1 = 2 Judgment is very important and the most important step, because if you do

Instance: http://www.xxx.com/jiaren.asp? Id = 544 Okay. Now we start ..... 1. Judgment Use ';Use and 1 = 1 and 1 = 2 Judgment is very important and the most important step, because if you do not know how to continue with manual injection ..==

Excel table processing data is very powerful, in the work, often need to look up from the database file index data to another file, how to implement this reference? by VLOOKUP function, you can do it easily. The VLOOKUP function is a portrait

Oracle left join... ON... AND... and left join... ON... WHERE... difference about left join... on... and... and left join... on... the difference between where is that many online statements are about left join... on... and ..., and conditions only

In Oracle, to improve SQL Execution efficiency, You need to reduce hard parsing to achieve sharedcursor sharing. The most common method is to bind variables. In Oracle, to improve SQL Execution efficiency, You need to reduce hard parsing to achieve

CREATE OR REPLACE FUNCTION cux_exec_sql (p_sql in VARCHAR2)RETURN numberAsL_CNT number;BEGINEXECUTE IMMEDIATE p_sql into l_cnt; RETURN l_cnt;EXCEPTIONWhen OTHERSThenRETURN 0;END; --drop TABLE Cux_tables_counter; CREATE TABLE Cux_tables_counter

Select(SELECT COUNT (*) from DEVICE0 where status! = 0),(SELECT COUNT (*) from Device1 where status! = 0),(SELECT COUNT (*) from Device2 where status! = 0),(SELECT COUNT (*) from device3 where status! = 0),(SELECT COUNT (*) from Device4 where status!