On top of echoing Jeff's concerns about deleting book details as sounding wrong/dangerous, I'd also question why are you trying to delete book details?

If it's about performance, then make sure...

RedGate knows: https://www.red-gate.com/products/sql-development/sql-prompt/pricing

($179 for 1 license)

1. You can do it in batches  -- e.g.,

   DECLARE @batchCount INT = 4000;
   DECLARE @deleteCount INT = 4000;
   
   WHILE @deleteCount = @batchCount 
       BEGIN
     ...

Install & use SSMS locally.

Don't run SSMS on the server. You don't want the overhead or security risks of remote desktop, let alone SSMS, on the server if you can...

Just get the two dates and use them in your where clause with IN()...

DECLARE @today DATE = (SELECT GETDATE());

DECLARE @firstOfMonth DATE = DATEADD(day, 1, EOMONTH(@today, -1))

WHERE Date...

Were the first and third choices deliberately identical?

SQLNCLI11 is only compatible back to SQL 2005. You could try creating a linked server using and ODBC data source and use the DSN in the linked server with...

Just to be sure, when you say "VSS", are you good folks talking about "Visual Source Safe"?

Probably Volume Shadow Copy Service? Though I didn't know it left debris.

And probably homework.

2008 introduced assignment of variable in declare statement.

1. Please format your code so it doesn't scroll horizontally out-of-sight for several furlongs. 🙂
2. You have no trigger and did a direct update to dbo.store_customers, not watermarktable, and did...

A case statement should work if there aren't too many variations -- e.g., something like

UPDATE table1 
SET FK_category = CASE WHEN name1='John' and name2='Doe' THEN 1000 
...

I suspect this line should use IIF like the others, shouldn't it?

-SUM(IF(Fields!strType.Value="Rent_Tax",Fields!intDT.Value,0))

Pictures don't provide any detail to analyze and aren't very useful.

Attaching an actual execution plan, or posting a link to actual plan on PasteThePlan would be much more useful.

If they were bits, you could use the NOT operator (~) -- i.e.,

UPDATE dbo.table_name SET column = ~column