Yes, I believe you reading of the original plan was correct.

I believe the error was because the first data type returned by the CASE is a varchar -- specifically 'Default Memory Settings - needs to be configured' -- and thus...

You can fix the immediate problem by changing the code like so:

else cast(value_in_use as varchar(50)) end as SQLMemoryInUse

I'd expect maybe a Shared lock and even a Schema lock on the table, but I don't think SQL would need to exclusively lock the table.

If you CAST the value to a different data type, such as decimal, SQL will automatically round the value for that type, so you will have to do a ROUND...

Should I add the Semester_ID Reference here?

I guess.  What you really need to do is step back and do a true logical data model first including normalization.  Your current table structures...

Also, btw, the data model you have is not correct.  You should have a separate "master" Course table, with nothing about semester in it, that contains core info about...

It's likely your PK on Inventory should be ( WarehouseID, ProductID ), at least based on that query (of course if you have a significant number of queries that use...

I'd need directly usable sample data for the holiday table -- CREATE TABLE and INSERT statement(s) -- to correct this for you.

The problem is that you multiplied the minutes difference by 60; just get rid of the "60*".

SELECT  CONVERT(CHAR(5), DATEADD(MINUTE, (DATEDIFF(MINUTE,CAST(@hFrom +':'+@mFrom AS TIME), CAST(@hTo +':'+ @mTo...

> Missing the point on this last one - you have multiple joins, not just 1 join. <<

It depends on how you look at it.  The view itself has only...

DECLARE @job_name nvarchar(128)

SET @job_name = 'JobA'

SELECT
    job_name AS name,
    COALESCE(CAST(j.enabled AS varchar(1)), 'Job not present') AS enabled,
    CASE...

For SQL Express, you'd need to use the task scheduler in Windows directly, instead of using SQL Server jobs.  It's more of a pain, but it should work.

You should explicitly...

That's why I put the note: my EXISTS example does NOT reference an outer table.  A rare situation perhaps, but not impossible, more likely:

WHERE EXISTS(SELECT 1 FROM sys.tables WHERE name...

Wouldn't that count every reference as a "join", including a select from a single table?  And any other single select from a table.

SELECT ...

FROM dbo.table1

SELECT ...

FROM dbo.table1

WHERE EXISTS(SELECT 1 FROM...