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SQL Alter
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Синтаксис SQL 

ALTER TABLE table_name
ADD column_name datatype

ALTER TABLE table_name
DROP COLUMN column_name

ALTER TABLE table_name
ALTER COLUMN column_name datatype

Example 1

There is a table "Persons":

P_IdLastNameFirstNameAddressCity
1 Hansen Ola Timoteivn 10 Sandnes
2 Svendson Tove Borgvn 23 Sandnes
3 Pettersen Kari Storgt 20 Stavanger 

1
2

ALTER TABLE Persons
ADD DateOfBirth

Query Result:

P_IdLastNameFirstNameAddressCityDateOfBirth
1 Hansen Ola Timoteivn 10 Sandnes
2 Svendson Tove Borgvn 23 Sandnes
3 Pettersen Kari Storgt 20 Stavanger

Example 2

1
2

ALTER TABLE Persons
ALTER COLUMN DateOfBirth year

Remove columns

1
2

ALTER TABLE Persons
DROP COLUMN DateOfBirth

Query Result:

P_IdLastNameFirstNameAddressCity
1 Hansen Ola Timoteivn 10 Sandnes
2 Svendson Tove Borgvn 23 Sandnes
3 Pettersen Kari Storgt 20 Stavanger

Comments

 
+3 #1 Denis 2010-07-13 12:06 And if you want to specify a nickname in the title, ie for example instead of writing Adress Address. What to do? Quote
 
 
0 #2 Rufflet 2011-04-27 05:29 Dennis, you're confusing something.
What do you mean an alias?
Aliases are used in the selector (see section SQL Alias) Quote
 
 
0 #3 Pavel 2011-10-20 09:32 And if I want to change the number of characters in the column, the data in this column is not removed?
Is it right to my query:

Persons
ALTER COLUMN Address nvarchar (200) Quote
 
 
0 #4 снег 2011-12-27 19:47
And if you want to specify a nickname in the title, ie for example instead of writing Adress Address. What to do?

 Quote
 

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