Updating multiple rows in sql server
This can also be used to change the column to NULL if the column has no default and is defined to allow null values.Compound assignment operator: = Add and assign -= Subtract and assign *= Multiply and assign /= Divide and assign %= Modulo and assign &= Bitwise AND and assign ^= Bitwise XOR and assign |= Bitwise OR and assign Returns updated data or expressions based on it as part of the UPDATE operation.CURRENT OF Specifies that the update is performed at the current position of the specified cursor. 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.A positioned update using a WHERE CURRENT OF clause updates the single row at the current position of the cursor. To replace or modify large blocks of text, ntext, or image data, use WRITETEXT or UPDATETEXT instead of the UPDATE statement.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.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.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.
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.When a FILESTREAM field is set to NULL, the BLOB data associated with the field is deleted. WRITE(), to perform partial updates to FILESTREAM data. If an update to a row violates a constraint or rule, violates the NULL setting for the column, or the new value is an incompatible data type, the statement is canceled, an error is returned, and no records are updated.