sql query to compare two tables in different databases

This example describes how PHP uses PDO to connect and query SQL databases. Share to everyone for your reference. The specific implementation code is as follows: Copy Code code as follows: $login = "root"; $passwd = "MySQL"; try{ $db =new PDO (' Mysql:host=localhost;dbname=mysql ', $login, $passwd); foreach ($db->

First SQL statementSelect CompanyName GSMC,ZB Zhibiao from Left Join T_companycode on T_GSNDZB.GSBH=T_companycode.companyidQuery Result:A second SQL statementSELECT min(CompanyName) GSMC,cast(round(sum(T_xstj.hsje)/10000,2) asNumeric -,2)) Ndje fromT_xstj Left JoinT_companycode onT_companycode.companyid=T_XSTJ.GSBHwhere DateDiff( YearSjgetdate())=0 Group byGsbhQuery Result:Statements that are merged int

Label:SQL statements and their types1. SQL statements fall into three categories: ? ? DDL (Data Definition Language): CREATE, DROP, ALTER; ? ? DML (Data manipulation Language): SELECT, INSERT, UPDATE, DELETE; ? ? DCL (Data Control Language): COMMIT, ROLLBACK, GRANT, REVOKE; 2. Basic writing rules for SQL statements: ? ? The SQL statement should end with a semicol

Label:1. View the user tableSelect from Sys.tables Select from where type='U' Select from where xtype='U' where type or xtype value:U = user table S = system table V = view FN = scalar function TF = table function P = stored procedure TR = Trigger 　　D = defaults or Default constraints PK = PRIMARY KEY constraintF = FOREIGN KEY constraint UQ = UNIQUE constraint SELECT from Information_schema. TABLES2. View ViewSELECT * from Information_schema. Views3. View the table/view fieldsS

the table and delete the table are as follows:Use Studbif exists (select * from sysobjects where name= ' Stumarks ')drop table StumarksCREATE TABLE Stumarks( Examno int identity (primary) key, Stuno char (6) NOT NULL, Writtenexam int not null, Labexam int not null)Go--Where the column attribute "identity (start value, increment)" means "Examno" is automatically numbered, also known as the identity columnALTER TABLE table nameAdd constraint constraint name

mssql2000 database execution SQL statements to create databases and data tables and indexesCreate a database MSsql2000Create DATABASE DatabaseName on Primary(Name= ' databasename_data ', filename= ' C:\databasename_data.mdf ', size=3mb,maxsize=unlimited,filegrowth=10%) log on(Name= ' Databasename_log ', filename= ' C:\databasename_log.ldf ', size=3mb,filegrowth=1

WangWu 21 A1003 ZhouLiu 22 A1004 SunQi 22Note that after you set the number of query bars to 5 and the query succeeds, you must have a "SET ROWCOUNT 0" statement, or you can return up to 5 data at the next execution.For example, we first execute the following statement:set5selectfrom tb_employeeinfoThe result returned is

Oracle The paging query statement of Oracle can basically follow this article. The next article will explain it through examples. Next we will briefly discuss the situation of Multi-table join. For join queries of the most common equivalent tables, CBO may use two join Methods: nested loop and hash join (merge join is less efficient than hash join, which is not considered by CBO in general ). Because paging

table Student_course_tableCREATE TABLE Student_course_table(StudentID varchar FOREIGN key references student_table (StudentID),CourseID varchar FOREIGN key references course_table (CourseID),Grade int)GoINSERT into student_course_table values (' 101 ', ' 001 ', 67)INSERT into student_course_table values (' 101 ', ' 002 ', 77)INSERT into student_course_table values (' 102 ', ' 001 ', 97)INSERT into student_course_table values (' 102 ', ' 002 ', 57)GoSELECT * FROM Student_course_tableThis article

Android SQL statements enable addition, deletion, modification, and query of databases. androidsql This topic describes how to add, delete, modify, and query databases in android. Review SQL Syntax: * Add Insert into info (name, p

Tags: style color strong data AR 2014 problem adThe operational database today is experiencing a problemThe target table ra_ad_daily_data about 50 million of the data, where the business_date field is a date typeI'd like to check the three records that were imported on August 20, and I'm just starting this way:SELECT * from Ra_ad_daily_data WHERE to_char (business_date, ' yyyy-mm-dd ') = ' 2014-08-20 ';The speed is very slow, five minutes or so to come out results (in PL/

Query all databases Select [name] from [sysdatabases] order by [name] Query all tables in a database Select [id], [name] from [sysobjects] where [type] = 'U' We all know that [type] = 'U' is a user table, and [type] = 's' is a system table. Based on the query result of

1.1:specifying Column Formats and Labels (SAS enhancements. )procSQL Outobs= the; Title'Current Bonus Information'; Title2'Employees with salaries > $75,000'; /* Title can be placed before SQL or between SQL and select */ SelectEmpid Label='Employee ID',/*label= is placed after the variable */Jobcode label='Job Code', salary, ' salary is: ', Salary*.Ten asBonus/* inserts a fixed set of character constants

This article describes in detail how to sort combined queries in SQL statements. if you are interested, refer to the following. SQL statement (several tables are combined for query to obtain the first to tenth data records ): 1. for example, tables A, B, C, and D are ass

Query all databases Select [name] from [sysdatabases] Order by [name] Query all tables in a database Select [ID], [name] from [sysobjects] Where [type] = 'U' We all know that [type] = 'U' is a user table, and [type] = 's' is a system table. Based on the query result of the p

1. Multi-Table Query1) Descartes Set: SELECT * FROM table name 1, table name 2 SELECT * FROM table name 1, table name 2 where table name 1. field name = Table Name 2. Field Name Note: If there are two fields with the same name, the table name (alias) will be used. Order BY is placed after the where condition. 2) Self-connection: The connection query for the same table, which treats a table as two

A combined query of SQL two tables uses join onFor example: Two table queries:Select U.username, T.title where User U is used to simplify the table name join is to join the other table on is the condition that represents the query U.username is the username field in the user tableThe same principle of multi-table

There is a requirement that it create a SQL Server query that includes cumulative values based on the event time. A typical example is a bank account, because you are saving and taking money at different times each time. For any account, at a point in time to calculate its borrowing (deposits) and credit (withdrawal) of the sum. After each transaction, you want t