sql server modify column

1: Add a field to the tableAlter table [table name] add [column name] Type2: Delete FieldAlter table [table name] Drop column [column name]3: Modify the field type in the table (you can modify the type of the column, whether it is

name+ '],' from#行数据中的需要转成列标题的数据--one more, get rid of it.IF(@sql Stitching Final column != "' ) BEGIN SET @sql Stitching Final column = @sql Stitching Final column + '$' SET @

modify the identity column of the table. (3) To set the benefits of an identity column The identity column is automatically incremented, starting at the seed, incrementing by increments, and set by the increment bit itself. For example: The seed is 1, the growth rate is 1, then the value of the identity

Uncover new features of SQL Server 2014 (3)-updatable column storage clustered index, Introduction The column storage index actually exists in SQL Server 2012, but SQL

SUM( CaseWEEK when 'Monday' ThenINCOMEEND) as [Monday],SUM( CaseWEEK when 'Tuesday' ThenINCOMEEND) as [Tuesday],SUM( CaseWEEK when 'Wednesday' ThenINCOMEEND) as [Wednesday],SUM( CaseWEEK when 'Thursday' ThenINCOMEEND) as [Thursday],SUM( CaseWEEK when 'Friday' ThenINCOMEEND) as [Friday],SUM( CaseWEEK when 'Saturday' ThenINCOMEEND) as [Saturday],SUM( CaseWEEK when 'Sunday' ThenINCOMEEND) as [Sunday] fromWeek_incomeHowever, a simpler approach is provided in

Note: SQL Server 2005 and above support. Version estimates are not supported (working environment 2005,2008). To work, you need to add a new column to the existing table in SQL Server and add a description. Thus there is a stored procedure as follows. (Attach the stored pro

In daily SQL Server development, identity columns of the Identity type are often used as the auto-increment numbers of a table structure. For exampleArticleNumber, record number, and so on. The reference of the Self-increasing ID column greatly facilitates the databaseProgramDevelopment, but sometimes this stubborn field type also brings some trouble. 1.

should look like this:Monday Tuesday Wednesday Thursday Friday Saturday Sunday1000 2000 3000 4000 5000 6000 7000In this case, SQL query statements can be written like this:SELECT SUM (case WEEK "Monday ' then INCOME end" as [Monday],sum (case WEEK, "Tuesday" then INCOME END) as [Tuesday],sum (case WEEK when "Wednesday ' then INCOME END" as [Wednesday],sum (case WEEK "Thursday ' then INCOME END" as [Thursday],sum (case WEEK "Friday" Then INCOME END)

ConstraintName? 1 ALTER TABLE student DROP CONSTRAINT PK__student__2F36BC5B772B9A0B 10. Adding field constraints Format: ALTER TABLE tablename ADD constraint ConstraintName primary key (column_name) --Example 1? 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 ALTER TABLE stuInfo ADD CONSTRAINT PK_stuNo PRIMARY KEY (stuNo) --示例2 添加主键约束（Primary Key）-- 存在主键约束PK_stuNO，则删除 IF EXISTS(SELECT * FROM sysobjects WHERE name=‘PK_stuN

The traditional relational database service engine is often not the best platform for analyzing and computing ultra-large amounts of data, so SQL Server has developed an analytics service engine to analyze and calculate large amounts of data. Of course, for the data storage platform SQL Server database engine, there is

Tags: sys http alt compute VIA--mount Ges StudioThe computed column differs from the column that requires us to assign the value manually or by the program, whose value is derived from the computed value of the other columns in the table. For example, if a table contains a quantity column number and a price column, we

on each row and points to the page where the data resides. He looks like a Chinese dictionary based on the ' radicals ' to find the word, even if the data is not sorted, but he has a directory more like a directory, the efficiency of data extraction is also a room for improvement, without the need for a full table scan.A table can have multiple nonclustered indexes, and each nonclustered index provides a different sort order based on the different indexed columns.viii. use of indexes1, the crea

However, Microsoft SQL Server has an important flaw in processing such indexes, which is to index the operations that should be compiled into the index seek, which can cause severe performance degradation Let me give you an example to illustrate the problem. Assuming that a table T has an index (Cityid, Sentdate, UserID), and now has a paging list feature, to obtain a query that is larger than a number of

Tags: 0kb run image MSDN Time Ash add view pngObjectiveIn the previous section we ended the description of hash Match aggregate and stream aggregate, this series we talk about computed column issues in SQL Server, short content, in-depth understanding, always to review the basics.Preliminary discussion of computed column