Updating a table from another table in sql server
Common table expressions can also be used with the SELECT, INSERT, DELETE, and CREATE VIEW statements.
In particular, filter or join conditions applied on the result of one of those calls have no effect on the results of the other.
Any characters not found in this code page are lost.
DEFAULT Specifies that the default value defined for the column is to replace the existing value in the column.
The results of an UPDATE statement are undefined if the statement includes a FROM clause that is not specified in such a way that only one value is available for each column occurrence that is updated, that is if the UPDATE statement is not deterministic. Modifying a text, ntext, or image column with UPDATE initializes the column, assigns a valid text pointer to it, and allocates at least one data page, unless the column is being updated with NULL.
For example, in the UPDATE statement in the following script, both rows in USE Adventure Works2012; GO IF OBJECT_ID ('dbo. To replace or modify large blocks of text, ntext, or image data, use WRITETEXT or UPDATETEXT instead of the UPDATE statement.