compare two columns in sql

The SQL scripts recommended in this article are all very practical. I learned how to study them together. The SQL scripts recommended in this article are all very practical. I learned how to study them together. Exchange of rows and columns The Code is as follows: Create table test (id int, name varchar (20), quarter int, profile int) Insert into test values (1,

Server Informal discussion on identity columns in SQL Server (i) I. Definition and characteristics of the identity column The identity column in SQL Server, also known as an identifier column, is customarily called a self-added column. The column has the following three features: 1. The data type of the column is a numeric type with no decimal number 2, in the

Exchange of rows and columns CopyCode The Code is as follows: Create Table Test (ID int, name varchar (20), quarter int, profile INT) Insert into test values (1, 'A', 1,1000) Insert into test values (1, 'A', 2,2000) Insert into test values (1, 'A', 3,4000) Insert into test values (1, 'A', 4,5000) Insert into test values (2, 'B', 1,3000) Insert into test values (2, 'B', 2,3500) Insert into test values (2, 'B', 3,4200) Insert into test values (2, 'B',

(SelectDistinct professional fromStu asaSet@sql ='Select study number,'[Email protected]+'From Stu GROUP by study number'exec (@sql) go-----use ISNULL ()-----DECLARE @sql varchar (8000)Select@sql =isnull (@sql +',',"') + Professional fromStu GROUP BY professionalSet@

filtering process SN = synonym TR = SQL DML Trigger IF = SQL Inline Table-valued function TF = SQL Table-valued function U = table (user-defined type) UQ = UNIQUE Constraint V = view X = Extended Stored P

Label:If the Select section contains columns that are not required, this forces DB2 to go to the data page to get the specific columns requested, which requires more I/O operations. In addition, if you sort this unwanted column, you need to create and pass a larger sort file, which will make sorting more expensive.If more than one table is involved in a query, specifying extra

SQL Server converts rows to columns: for example, if a table contains only a small amount of data, you can use static SQL statements such as selectstuName and max (caseCoursewhen language thenscoreelse0end) as language, max (caseCoursewhen math thenscoreelse0end) as math, max (caseCoursewhen SQL Server transfers rows t

Label:Data from the database in the work to export, but found that the exported Excel column names are field names (in English), to collect data on how to change the field name to Chinese names, and found that Oracle and SQL Server (SQLSERVER2008R2) is different, as follows: SQL Server database: system table: ---Get information about a tableSELECT * from SYS. OBJECTS(Description: Name: Table name object_id:

fast and efficient because:The truncate table function is the same as the DELETE statement without the WHERE clause: both DELETE all rows in the TABLE. However, truncate table is faster than DELETE and uses less system and transaction log resources.The DELETE statement deletes a row at a time and records one row in the transaction log. Truncate table deletes data by releasing the data pages used to store TABLE data, and only records the release of pages in transaction logs.Truncate table delete

Label:Find the maximum value for multiple columns in one row in a SQL Server table Sometimes we need to find the largest value from multiple identical joins (the same data type for these columns) and show Here is an example IF(object_id('tempdb: # #TestTable') is not NULL) DROP TABLE# #TestTableCREATE TABLE# #TestTable (IDINT IDENTITY(1,1)PRIMARY KEY, NameNV

How does the column selection differ when Oracle queries are converted to SQL queries? The following describes how to select columns from Oracle query to SQL query. We hope that you can have a deeper understanding of Oracle query. When converting an Oracle query to an SQL Server, you must be careful about some issues t