Updating table variables
Temporary tables are preferred when cost-based choices are required.This plan typically includes queries with joins, parallelism decisions, and index selection choices.That way I could execute some query on the table variable in one part of the procedure, and then later execute some code for each row in the table variable. DECLARE @Rows To Process int DECLARE @Current Row int DECLARE @Select Col1 int DECLARE @table1 TABLE (Row ID int not null primary key identity(1,1), col1 int ) INSERT into @table1 (col1) SELECT col1 FROM table2 SET @Rows To [email protected]@ROWCOUNT SET @Current Row=0 WHILE @Current Row DECLARE @Rows To Process int; DECLARE @table1 TABLE (Row ID int not null primary key identity(1,1), col1 int ) INSERT into @table1 (col1) SELECT col1 FROM table2 SET @Rows To Process = @@ROWCOUNT WHILE @Rows To Process You can loop through the table variable or you can cursor through it.This is what we usually call a RBAR - pronounced Reebar and means Row-By-Agonizing-Row.Modify the format of the Salary column and delete the Phone column.The ALTER TABLE statement specifies EMPLOYEES as the table to alter.table variables aren't supported in the SQL Server optimizer's cost-based reasoning model.
The DROP clause permanently drops the Phone column.The only constraint types allowed are PRIMARY KEY, UNIQUE KEY, and NULL.For more information about the syntax, see CREATE TABLE (Transact-SQL), CREATE FUNCTION (Transact-SQL), and DECLARE @local_variable (Transact-SQL).You can also perform more complicated updates in Oracle.
You may wish to update records in one table based on values in another table.
Transact-SQL Syntax Conventions Is the same subset of information that is used to define a table in CREATE TABLE.