Differences and use of Update,alter,modify,delete,drop in SQL (collation)

About UPDATE and ALTER:

Baidu knows about the update and alter has a very image of the summary: A table has a lot of fields, a field has a lot of data. A family has a lot of rooms, a room with a lot of furniture. Update is used to change the wardrobe to a bookshelf. Alter is used to change the kitchen into a toilet.

Change the bedroom to a toilet: ALTER TABLE your home changes kitchen toilet varchar (8);

Add a toilet to your home: ALTER TABLE your home add toilet varchar (8); (8 means 8 square meters of toilet)

Modify toilet size: ALTER TABLE your home modify (toilet varchar (100));

Name the toilet: ALTER TABLE Your home rename column toilet to toilet;

Destroy toilet: ALTER TABLE your home drop column toilet;

and change the wardrobe to a bookshelf: Update your home set wardrobe = bookshelf where ...; (without where, all the closets in the room became bookshelves). Update your home set wardrobe =null where ...; Delete the wardrobe.

Delete and drop:delete remove the wardrobe or delete the Bookshelf; Drop is the delete room; Delete a wardrobe: delete from your home where id= wardrobe; Even if the data is deleted, the table structure is still there. Delete a toilet: ALTER TABLE your home drop column toilet;

Delete a database: Drop your home;

Http://www.cnblogs.com/lamian/p/3972562.html

The difference and use (collation) of Update,alter,modify,delete,drop in SQL (GO)