Dynamic Update statement

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Hi Friends,

Here i am using the cursor in my store procedure, i am planning to take out my cursor in my SP , please give some solution how to avoid the cursor statement to normal update statement with dynamic .

Example Below:

Update Tablename set columnname(variable) = value from table A join Table B on A.condition = B.Condition where name = 'Test'(variable) and age = 18(variable)

Update Tablename set columnname(variable) = value from table A join Table B on A.condition = B.Condition where name = 'kumar'(variable) and age = 19(variable)

3 Update Tablename set columnname(variable) = value from table A join Table B on A.condition = B.Condition where name = 'babu'(variable) and age = 30(variable)

This is how my cursor will work 300 Combination dynamically pick the data from table and update into the main table

I am trying to take out the cursor , and update statement should work similar like this , instead of writing 300 update statement i want to write one update where all the 300 combination should execute.

below the code i have to bring another solution.

SQL

BEGIN DECLARE @Type VARCHAR(100)
DECLARE @TargetColumn VARCHAR(100)
DECLARE @SourceColumn VARCHAR(100)
DECLARE @SQL varchar(max)

DECLARE a_cursor CURSOR STATIC
FOR
SELECT [Type],[SourceColumn],[TargetColumn] FROM ref.tblEdsMap
GROUP BY [Type],[SourceColumn],[TargetColumn]
OPEN a_cursor
FETCH NEXT FROM a_cursor INTO @Type,@SourceColumn,@TargetColumn
WHILE @@FETCH_STATUS = 0
BEGIN

SET @SQL = 'UPDATE GCT SET GCT.' + @TargetColumn + ' = map.[TargetValue]
from EdsMap map
JOIN Table GCT
ON GCT.' + @SourceColumn + ' = map.[SourceValue]
where map.[Type]=''' + @Type + ''' and map.SourceColumn=''' + @SourceColumn+ ''''
Exec (@SQL)
PRINT @SQL
FETCH NEXT FROM a_cursor INTO @Type,@SourceColumn,@TargetColumn
END
CLOSE a_cursor
DEALLOCATE a_cursor
END

Posted 24-Jul-13 7:36am

Member 9781397

Updated 24-Jul-13 8:27am

Maciej Los

v4

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Comments

ZurdoDev 24-Jul-13 13:47pm

If the cursor works, why change it?

Member 9781397 24-Jul-13 13:50pm

Hi Friend, Cursor is working fine but i have 95Lak records is there in the table and i have to update 30 column with different combination so performance wise i fell very bad and am looking for better approach to avoid cursor

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Adarsh chauhan · Answer 1 · 2013-07-24T20:06:00

hi,

see if it works fine for you...

BEGIN DECLARE @Type VARCHAR(100)
DECLARE @TargetColumn VARCHAR(100)
DECLARE @SourceColumn VARCHAR(100)
DECLARE @SQL varchar(max)
Declare @tblcount int
Declare @count int
 

SELECT ROW_NUMBER() OVER (ORDER BY [Type]) AS Row,[Type],[SourceColumn],[TargetColumn] into #temp 
FROM ref.tblEdsMap
GROUP BY [Type],[SourceColumn],[TargetColumn]


set @tblcount=(select COUNT(*) from #temp)
set @count=0

while(@count<@tblcount)
begin 

	select @Type=[Type],@SourceColumn=[SourceColumn],@TargetColumn=[TargetColumn] from #temp 
	where Row=@count;
	 
	SET @SQL = 'UPDATE GCT SET GCT.' + @TargetColumn + ' = map.[TargetValue]
	from EdsMap map
	JOIN Table GCT
	ON GCT.' + @SourceColumn + ' = map.[SourceValue]
	where map.[Type]=''' + @Type + ''' and map.SourceColumn=''' + @SourceColumn+ ''''
	Exec (@SQL)

	set @count=@count+1;
end

drop table #temp