Updating table variables

Microsoft is conducting an online survey to understand your opinion of the Technet Web site.If you choose to participate, the online survey will be presented to you when you leave the Technet Web site. UPDATE, however, does allow you to update a table column In the example above, we’re doing just this.

You create a table variable the same way you create any other variable: using the declare statement: This declares a table variable named @Table Var that we can use in place of a temporary table. When you create a table variable it only resides in memory which means it's much faster.create table Employee( 2 ID VARCHAR2(4 BYTE) NOT NULL, 3 First_Name VARCHAR2(10 BYTE), 4 Last_Name VARCHAR2(10 BYTE), 5 Start_Date DATE, 6 End_Date DATE, 7 Salary Number(8,2), 8 City VARCHAR2(10 BYTE), 9 Description VARCHAR2(15 BYTE) 10 ) 11 / Table created.SQL select * from Employee 2 / ID FIRST_NAME LAST_NAME START_DAT END_DATE SALARY CITY DESCRIPTION ---- -------------------- -------------------- --------- --------- ---------- ---------- --------------- 01 Jason Martin 25-JUL-96 25-JUL-06 1234.56 Toronto Programmer 02 Alison Mathews 21-MAR-76 21-FEB-86 6661.78 Vancouver Tester 03 James Smith 12-DEC-78 15-MAR-90 6544.78 Vancouver Tester 04 Celia Rice 24-OCT-82 21-APR-99 2344.78 Vancouver Manager 05 Robert Black 15-JAN-84 08-AUG-98 2334.78 Vancouver Tester 06 Linda Green 30-JUL-87 04-JAN-96 4322.78 New York Tester 07 David Larry 31-DEC-90 12-FEB-98 7897.78 New York Manager 08 James Cat 17-SEP-96 15-APR-02 1232.78 Vancouver Tester 8 rows selected.Including CREATE TABLE and INSERT statements usually helps.State what version of SQL Server you are using and specify the content of any error messages. For instance, consider the following example: DECLARE @tbl TABLE ( ordinal int NOT NULL, word varchar(100) NOT NULL, PRIMARY KEY CLUSTERED (ordinal) ); INSERT INTO @tbl (ordinal, word) VALUES (1, 'This'), (2, 'is'), (3, 'a'), (4, 'test'), (5, 'of'), (6, 'string'), (7, 'concatenation'); DECLARE @output varchar(1000)=''; On a side-note: We looked at a more advanced string concatenation example, using XML, in a previous post.Just like the SELECT statement, the UPDATE statement executes row-by-row on the table being updated.Contents Caveat This answer discusses "classic" table variables introduced in SQL Server 2000.SQL Server 2014 in memory OLTP introduces Memory-Optimized Table Types. Both are stored in tables but table variables can use them from the current database (Source). As Aaron points out in the comments the behavior of temporary tables in these differs ) or when the session ends otherwise.This means that the SET clause of the UPDATE statement is evaluated once for every row in the updated table.With the SELECT statement, you can’t assign variables and return an output in the same statement.

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