If the object being updated appears more than one time in the FROM clause, one, and only one, reference to the object must not specify a table alias. Table2 (d1 int PRIMARY KEY NOT NULL, d2 int NOT NULL); GO INSERT INTO dbo. Table2 VALUES (1, 20), (2, 30); GO DECLARE abc CURSOR LOCAL FOR SELECT c1, c2 FROM dbo. Table1; GO Support for use of the READUNCOMMITTED and NOLOCK hints in the FROM clause that apply to the target table of an UPDATE or DELETE statement will be removed in a future version of SQL Server.
All other references to the object in the FROM clause must include an object alias. Avoid using these hints in this context in new development work, and plan to modify applications that currently use them.
Use caution when specifying the FROM clause to provide the criteria for the update operation. Table2 (Col A int PRIMARY KEY NOT NULL, Col B decimal(10,3) NOT NULL); GO INSERT INTO dbo. Minimal logging is not used when existing values are updated.
CURRENT OF Specifies that the update is performed at the current position of the specified cursor. If the UPDATE statement could change more than one row while updating both the clustering key and one or more text, ntext, or image columns, the partial update to these columns is executed as a full replacement of the values.
This process of extracting the elements of a collection is called refers to a LOB object attribute, then you must first initialize it with a value of empty or null. Also, if you are updating a LOB value using some method other than a direct to set the column to the value previously specified as the default value for the column.
If no default value for the corresponding column has been specified, then the database sets the column to null.
For more information, see @@ROWCOUNT (Transact-SQL). Variable names can be used in UPDATE statements to show the old and new values affected, but this should be used only when the UPDATE statement affects a single record. Use nvarchar(max), varchar(max), and varbinary(max) instead.) clause to perform a partial or full update of varchar(max), nvarchar(max), and varbinary(max) data types.
If the UPDATE statement affects multiple records, to return the old and new values for each record, use the OUTPUT clause. Table1 (Col A int NOT NULL, Col B decimal(10,3) NOT NULL); GO CREATE TABLE dbo. For example, a partial update of a varchar(max) column might delete or modify only the first 200 characters of the column, whereas a full update would delete or modify all the data in the column. WRITE updates that insert or append new data are minimally logged if the database recovery model is set to bulk-logged or simple.
TOP ( ) Specifies one or more table hints that are allowed for a target table. If 'N' is not specified, SQL Server converts the string to the code page that corresponds to the default collation of the database or column.