If you really want to remove the date from the column, then change the column type to "time".

Dates, datetimes and times are stored in a special binary format in SQL Server.  You don't change the column format, you just change the display format.

SELECT CONVERT(varchar(8), datetime_column, 8)

Yes, Oracle is extremely difficult to learn.  Their syntax is overall an odd mix of SQL style and earlier language styles.

No directly usable sample data, so I can't test it, but maybe this:

DECLARE @first_week_ending_date date;
SET @first_week_ending_date = '20240707';

SELECT 
    ClientID,
    DATEADD(DAY,...

Hmm, are you using SSMS / gui to see the tables?  Maybe there is a filter set for schema=dbo?

Good point.  I was in too much of a hurry when I wrote the other code:

DECLARE @x varchar(500) = 'xxx.  #1234 has been replaced by #014521...

An alternative (maybe slightly less overhead?, esp. for long strings):

SELECT LEFT(item, CHARINDEX(' ', item + ' ')) AS value
FROM dbo.DelimitedSplit8K (@x, '#') /*or STRING_SPLIT(), if available to...

I suggest removing ALL non-numeric values in the query itself rather than trying to go thru the data.  For example, by making this mod to the query:

...
...

No DDL provided, but my best guess is that one of these columns:

t1.invoicenum; t2.invoicenum

is integer and the other is not, and that one contains a value of 'VZ34-031'

Since they are "or" conditions, SQL should be able to stop evaluating at the "first" one that is true.  In theory, though, SQL could re-arrange the checks and make a...

I think this will match what you need, if I understand correctly:

SELECT ...

FROM dbo.baseTable bt

LEFT OUTER JOIN dbo.sentTable st ON st.sent_rowid = bt.rowid

WHERE ((@vendor IS NULL AND st.sent_rowid IS NULL)...

If you only want to replace leading and/or trailing commas, then this:

UPDATE tn
SET oppo_SCRMcompetitor = CASE WHEN LEFT(oppo_SCRMcompetitor_ca1, 1) = ',' 
    THEN STUFF(oppo_SCRMcompetitor_ca1,...

If you always want to replace every comma, you can do this:

UPDATE dbo.table_name

SET oppo_SCRMcompetitor = REPLACE(oppo_SCRMcompetitor, ',', '')

WHERE oppo_SCRMcompetitor LIKE '%,%'

That is SQL's method for handling insufficient space on a CAST.

The only safe method would be to use 11 chars. 10 max digits plus the prefix char (assuming you don't...

Definitely focus on the clustered index, first and foremost!

The best way to choose the keys is to look at the missing index stats and current index usage stats and decide...