select count 1

--The vast majority of dba/all/user/v_$/gv_$/session/index begins with a view--dba_tables means all the relational tables that the DBA has or can access. --All_tables All relational tables that a user has or can access. -User_tables means all the

1 Problem descriptionPreviously wrote a blog to delete the Oracle home directory, refer to:Linux platform mistakenly delete home Oracle root directory solutionhttp://blog.csdn.net/tianlesoftware/article/details/43794273This is the depth of this side,

First, how to enter the sqlite3 interactive mode for command operation?1. Confirm whether the Sqlite3 is installedGo to the python command line and execute>>> Import sqlite3>>>No error, indicating that Sqlite3 has successfully installed the2. How to

For the left, right, and inner keywords, pay attention to the details. The details are very important! For example, remember to add comments when writing code! 1. Typographical editing-when writing SQL statements, especially writing batches, be sure

Detailed usage of count (), group by, and order by in mysql, and detailed usage of mysql I encountered a problem when I was doing IM recently and used these three keywords at the same time. This is to query the offline message details of a person.

SQL query used in oracle development the number of levels 2, 3, and 4 under the level 1 category SQL code SELECT temp. cname, temp. rootcid, (select count (1) FROM show_tb_category t1 WHERE t1.flag = 2 AND t1.rootcid = temp. rootcid) category2,

A new feature in Oracle11g is the Partition Table of the system. Here is an experiment: SQLgt; select * fromv $ version; BANNER ------------------------- A new feature in Oracle 11g is the Partition Table of the system. Here is an experiment: SQLgt;

I remember when I used FoxPro, I had to write a special process for ranking. It was very complicated and I had to consider the parallel ranking. Now I only need one SQL statement:/* Ranking statement --- County rankingSelect name, total score,

First, log data analysis1. Background1.1 * * * Forum log, the data is divided into two parts, the original is a large file, is 56GB, after a day to generate a file, about 150-200MB between;Each row of records consists of 5 parts: 1. Access to ip;2.

Background: The t_t_busi_main_presend and limit tables are similar (t_busi_main_presend3 has 0.92 million data before cleaning, and t_busi_main_presend is 0.8 million), but multiple limit records can be remitted to one t_busi_main_presend. Now clear

Before introducing flashback, we will introduce undo_retention-related parameters.  Undo_retention: indicates the expiration time of Undo data. The default time is 900 or 15 minutes. However, it should be noted that the prerequisite for ensuring

-- SQL2000Select max (T. col1) as ID, T. col2, count (1) CNTFrom (select col1, col2, rownum = (select count (1)From TBWhere col2 = A. col2 and col1 From tb a) TGroup by T. col2, T. col1-rownum /*Id col2 CNT---------------------------------1 1 13 9 21

Use Goldengate Initial Data Load, goldengateinitial When building ogg, we usually need to initialize the target Library first, so there are many initialization methods. Now we will introduce ogg's own initialization method. Test environment: Souce

Someone recently proposed to view the Postgresql execution plan. The following describes how the cost and other related values in the PG execution plan are calculated:PG version 9.1.21. Use the terminal tool PGADMIN to press F7 to execute the

Select *, (select count (1)From personal ranking BWhere personal ranking. unit = B. UnitAnd personal ranking. Final score> B. Final score) As row numberFrom personal ranking where(Select count (1)From personal ranking BWhere personal ranking. unit =

These days idle boring, want to surf the internet down a few movies to see, looking for is to be money, bad, spend time to go to the remittance is better to find a loophole black. So, the plan begins: (in order to avoid unnecessary misunderstanding,

First, understand the following functions Set variable length () function char_length () replace () function max () function1.1. Setting variable SET @ variable name = value Set @address = ' China-Shandong province-Liaocheng-Shen County '; Select

CREATE TABLE Egmas_count_data(Times date NOT NULL,COUNT number (+) is not NULL,System_name VARCHAR2 (+) NOT NULL,Operation_index VARCHAR2 (+) NOT NULL);--ADD comments to the columnsComment on column egmas_count_data. Timesis ' date ';Comment on

--Most of the dba/all/user/v_$/gv_$/session/index starts with a view-Dba_tables means all the relational tables that the DBA has or can access.--All_tables All relational tables that a user has or can access.-User_tables means all the relational

Problem Description:Query all data, query result: 146360Select Count (1 fromIn query get partial data, query result: 73080Select Count(1) fromBANK_CDE