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SQL While loop

patd1
patd1 asked
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Last Modified: 2015-03-31
I have a table with a 1 billion plus records, having fields timeID and UID , RID and some more.
There are multiple UID values associated with Each TimeID. Time ID starts with 164.

I want to run update on all records in smaller subsets to improve update efficiency. so I am doing a while loop such that it updates all records for one UID  for each time id. I have set timeID in the outer loop and UID in the inner loop. To be able to verify process, I am inserting timeID and UID in a table.

When I run this code, it runs all UID (-99, -88, 26 to 53) with time ID 164, which is good, but I am expecting this for all timeID from 164 to 1000. Please check my code and suggest why it is not showing me any other timeID except 164.


DECLARE @counter INT
DECLARE @min_count INT
DECLARE @max_count INT
DECLARE @sub_counter INT
DECLARE @Sub_min_count INT
DECLARE @sub_max_count INT

Truncate table dbo.Status_Update_myTable

--timeID
-- Query the table to find the starting timeID
SET @min_count = (SELECT Min(timeID) FROM   myTable)
PRINT 'Min timeID = '  + Cast(@min_count AS VARCHAR(8))

-- Query the table again to find the last Time ID
SET @max_count = (SELECT Max(timeID) FROM   myTable)
PRINT 'Max timeID = '  + Cast(@max_count AS VARCHAR(8))
---------------------------------------------------------------------
--UID
-- Query the table to find the starting UID
SET @Sub_min_count = -99 
PRINT 'Min UID = ' + Cast(@Sub_min_count AS VARCHAR(8))

-- Query the table again to find the last UID
SET @sub_max_count = (SELECT max(UID) FROM   myTable)
PRINT 'Max UID = ' + Cast(@sub_max_count AS VARCHAR(8))
--=====================================================================


-- Set Loop Control Variable Values
-- Set initial value (Min timeID Value - 1)
SET @counter = @min_count - 1
SET @sub_counter = @Sub_min_count -1

print @counter
print @sub_counter 


WHILE @counter < @max_count + 1 --Loop until counter greater than max Time ID
  BEGIN
      IF @counter = 212
        SET @counter = 999
      ELSE
        SET @counter = @counter + 1 --Increment Counter
      PRINT 'Updating timeID: '
            + Cast(@counter AS VARCHAR(8))

      WHILE @sub_counter < @sub_max_count + 1 --Loop until Sub counter greater than max UID
        BEGIN
            
            SET @sub_counter = @sub_counter + 1 --Increment Counter
            
            
            PRINT 'Updating UID: '
                  + Cast(@sub_counter AS VARCHAR(8))

            ---------------------------------------------------------
            -- Sample logic
            ---------------------------------------------------------
           --update statement here

            Select @counter,@sub_counter 
            INSERT INTO dbo.Status_Update_myTable
            (timeId, UID)
            SELECT @counter,@sub_counter  
            
            if    @sub_counter = -99 Set @sub_counter = -89 
            if    @sub_counter = -88 Set @sub_counter = 25         
                         
           ------------------------------------------------------------
           -- END logic
           ------------------------------------------------------------
        END  
                 
           
  END 

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