Solved

UPDATE from a SELECT

Posted on 2006-11-21
1
272 Views
Last Modified: 2008-02-07
Hi,

I want to create T-SQL stored procedure that will do the following task :

I have 2 tables. A and B. A and B have 4 fields in common. The fields are named F1, F2, F3 and F4. B is the reference table that contain an ID (say K1 as the field name) and the 4 fields (Fx). A is the data table that contains both the foreign key K1 and also the fields (Fx). So basically, I can do a select on table A and get by using relatinal data the related value of F1, F2, F3 and F4 using the foreign key of A.K1 and primary key of B.K1. But B is so big (millions records), I want to remove the relational for specific queries that has to be very fast and a so select on one table only (A). So periodically, I want to execute a stored procedure that will take the data from B and put them in A using both a SELECT (to get the related data) and an UPDATE (to update the table A).

Look this pseudo code, I want this in TSQL

ARECORDSTOBEUPDATED = SELECT ALL RECORDS FROM A THAT DO NOT CONTAIN F1 VALUE (this means we did not normalized it yet)

( FOREACH MAINDATAROW IN ARECORDSTOBEUPDATED DO:

  REFERENCEROW =  SELECT TOP 1 FROM B WHERE B.K1 = MAINDATAROW .K1

 UPDATE MAINDATAROW WITH REFERENCEROW DATA (F1, F2, F3, F4)
)

This is quite simple, but I really don't know how to achieve this.

Thanks a lot in advance.
0
Comment
Question by:pmengal
1 Comment
 
LVL 143

Accepted Solution

by:
Guy Hengel [angelIII / a3] earned 250 total points
ID: 17988120
update a
  SET F1 = B.F1, F2 = B.F2, F3 = B.F3, F4 = B.F4
from A
join B
  on A.K1 = B.K1
 and A.F1 IS NULL
0

Featured Post

Free Tool: Subnet Calculator

The subnet calculator helps you design networks by taking an IP address and network mask and returning information such as network, broadcast address, and host range.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
LTrim & Double Space Correction 5 40
SQL Pivot with row total 5 28
Access join syntax when converting to T-SQL query 4 34
Isolation level setting TSQL View 10 29
Slowly Changing Dimension Transformation component in data task flow is very useful for us to manage and control how data changes in SSIS.
I have a large data set and a SSIS package. How can I load this file in multi threading?
Via a live example, show how to extract information from SQL Server on Database, Connection and Server properties
Using examples as well as descriptions, and references to Books Online, show the different Recovery Models available in SQL Server and explain, as well as show how full, differential and transaction log backups are performed

828 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question