Sql updating multiple rows from another table canberra singles dating
You can improve the performance of an update operation by updating the table in smaller groups.
Consider the following code: The above code updates 10000 rows at a time and the loop continues till @@rowcount has a value greater than zero. Best practices while updating large tables in SQL Server1.
Hello, I'm trying to copy data from one table to another. The error I'm getting is ORA-01427: single-row subquery returns more than one row. You want to correlate the subquery with the parent query rather than including the svconstruct table in the subquery as well.
I would like to copy the date information from svjob.dttmstart to svjob.dttmconstruct where svjob.typ1 is like %onst%, however, I also need to ensure that the svjob is linked to the correctsite (svsiteheader). When I run the SELECT statement by itself, it returns 1053 rows. Try this: UPDATE svconstruct SET dttmconstruct = (SELECT svjob.dttmstart FROM svsiteheader JOIN svjob ON svsiteheader.idsite = svjob.idsite WHERE svsiteheader.idsite = svconstruct.idsite AND (lower(svjob.typ1) LIKE '%onst%') AND svjob.dttmstart IS NOT NULL), sysmoduser = 'svconstruct_dates', sysmoddate = sysdate WHERE EXISTS (SELECT 1 FROM svsiteheader JOIN svjob ON svsiteheader.idsite = svjob.idsite WHERE svsiteheader.idsite = svconstruct.idsite AND (lower(svjob.typ1) LIKE '%onst%') AND svjob.dttmstart IS NOT NULL) If that doesn't work, it might help to present more infomation about the tables in question, such as primary keys.
Many a times, you come across a requirement to update a large table in SQL Server that has millions of rows (say more than 5 millions) in it.
He started his career as a developer working with Visual Basic 6.0, SQL Server 2000 and Crystal Report 8.
As years went by, he started working more on writing queries in SQL Server.
When I try to update only the missing data the non-matched data is also updated but to NULL. The reason some of your rows are getting NULLs updated is due to the subquery.
When the subquery fails to find a matching row in tbl B, the subquery returns NULL.