Label:The first is the problem of fuzzy query, I started with the following conditions: SELECT * from the user where name like '% #value #% '. But how can not, as if also reported wrong. Later on the internet found a solution, is to use $ to replace the # number.1> write: Like '% $value $% ' can be,2> also found another method, but that method I tried for a long time, is not, the method is: like '% ' | | #value # | | '% ', the
Label:--sal for employee wagesSELECT * from EMP;--Inquire about employee information in the [1500,3000] range of wagesSELECT * from emp where Sal >= and Sal SELECT * from EMP where Sal between and 3000;--The above two sentences have the same effect--Query employee information for wages less than 1500 or greater than 3000SELECT * from emp where Sal SELECT * from emp where Sal is not between and 3000;--The above two sentences have the same effect--
[Name],subject,score Here for a good understanding only one column to get the following results With the example of the language accomplishment line train, it is easy to add the other two columns, Select [Name],Chinese =caseWhen subject= ' language ' then score else 0EndMathematics =caseWhen subject= ' math ' then score else 0EndForeign Language =caseWhen subject= ' foreign language ' then score else 0EndFrom StudentscoreGroup BY [Name],subject,score The following is the result of the
When converting Oracle queries to SQL queries, you need to pay attention to a lot of issues. The following gives you a detailed analysis of the number trade-offs in converting Oracle queries to SQL queries for your reference.
Number trade-offs
Oracle Database has a TRUNC function, which returns n digits of the m-bit decimal number. If m is omitted, n is 0 digits. The m value can be negative, indicating th
Php:It is usually the beginning of the code you want to check to record a time, the end of the record a time. Take the difference value,the efficiency of database SQLSQL explain (MySQL), enable slow query log to record slow queries. Usually also depends on the database design is reasonable, the demand is reasonable and so on.But this time is generally very fast, in less than a second, so you can not directly use mktime ()function Getmicrotime () {Lis
One
First you need to define a database interface function that can be saved as a single PHP page
functiondb_connect() {$result = new mysqli('数据库地址', '账号', '密码', '库名');//连接数据库if (!$result) { returnfalse;//连接失败 } return$result;//返回数据库对象}?>
Two
In another PHP page, the first use of the include函数 PHP page contains the above, it is necessary to ensure that the above interface functions can be called correctly
!--? php function Output_rows ( $seller _id ) { $conn = D
;--current session process ID
SELECT @ @textSize;
SELECT @ @version;--Current database version information
9. System Statistic function
SELECT @ @CONNECTIONS;--Number of connections
SELECT @ @PACK_RECEIVED;
SELECT @ @CPU_BUSY;
SELECT @ @PACK_SENT;
SELECT @ @TIMETICKS;
SELECT @ @IDLE;
SELECT @ @TOTAL_ERRORS;
SELECT @ @IO_BUSY;
SELECT @ @TOTAL_READ;--Read disk count
SELECT @ @PACKET_ERRORS;--Number of network packet errors that occurred
SELECT @ @TOTAL_WRITE;--sqlserver the number of disk writes p
Table:Reseller Dealer Field UID Parent_uid nameContact Contacts Field UID dealer_id contact_mainDemand:Want to inquire about the reseller's information, and the main contact information of this reseller, and the reseller's parent reseller's nameCaseThere may be parent_id that are nullSQL statements: SELECT dea.uid uid, dea.enabled_flag enabledflag, dea.delete_flag Deleteflag, dea.tenement_id Tenementid, dea.parent_id parentid, pd.name parentname,
Select A.name as table name, b.name as column name, c.name as type, b.max_length as Byte count, b.precision As Integer, B.scale as decimal from Sys.tables a INNER JOIN Sys.columns B on a.object_id=b.object_id inner join Sys. Types C on c.user_type_id=b.user_type_idThis article is from the "IT" blog, so be sure to keep this source http://8577754.blog.51cto.com/8567754/1553205How to use a statement in an SQL query
Hibernate native SQL query, Hibernate native SQL
Recently, a more complex query was made, and the basic query of hibernate could not meet the requirements. Therefore, we had to use the native SQL
SQL subquery, multi-Table query, and joint Query
Subquery, multi-Table query, and joint QueryThese three concepts are interpreted slightly differently in different SQL versions, roughly as follows:
JoinYou can check related SQL
I wrote a half-day SQL statement in the query analyzer and forgot to save it ~ What should I do if I want to retrieve an SQL statement that has been executed for a certain period of time?
I wrote a half-day SQL statement in the query analyzer and forgot to save it ~ What sho
Tags: that is greater than stronggrouplov in insert get address When we want to query all result sets in SQL for which a column value is NULL, the query condition should write like thisSELECT * FROM table where field is nullInstead, use the SELECT * from table where field = NULL to not find the correct result. Then why is this? To understand why, you need to
longitude and latitude two columns in the data table to optimize the speed at which the where statement executes.The final SQL statement is as follows
1
$sql=‘select * from users_location where
2
latitude >‘.$lat.‘-1and
3
latitude ‘.$lat.‘+1and
4
longitude >‘.$lon.‘-1and
An interesting SQL queryA friend has such a SQL query requirement:There is a login table (Tmp_test) that contains the user ID (UID) and logon time (Login_time). The table structure is as follows:*************************** 1. Row***************************Field:uidtype:int(Ten) unsignedNull: NOKey: MULDefault:NULLExtra:*************************** 2. Row**********
T-SQL query advanced-understanding the lock introduction in SQL Server, each query will find the shortest path to achieve their goals. If the database only accepts one connection, only one query is executed at a time. Therefore, queries must be completed quickly and easily.
Source: http://www.cnblogs.com/doosmile/archive/2012/03/16/2400646.html--Connect remote SQL or insert data with OPENROWSET--if it's just temporary access, you can use OPENROWSET directly--query ExampleSELECT * FROM OPENROWSET (' SQLOLEDB ', ' SQL Server name '; ' User name '; ' Password, database name. dbo. Table name)You need to enable AD HOC distributed for cro
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