T-SQL中来自一个源列表的多个表更新

Question

I have 3 tables that I wish to UPDATE data against (lets call them PROCESS , DIARY and HISTORY )

The 3 tables all have an ID column and the subset of data I wish to update is retrieved from a SELECT statement against the PROCESS table

SELECT ID FROM PROCESS WHERE STATUS = 1 AND COMPANY = 'XYZ'

Using T-SQL, I was planning to do 3 UPDATE statements (with the PROCESS table being last as it is the reference list) like so

UPDATE HISTORY ... WHERE ID IN (SELECT ID FROM PROCESS WHERE STATUS = 1 AND COMPANY = 'XYZ')
UPDATE DIARY ... WHERE ID IN (SELECT ID FROM PROCESS WHERE STATUS = 1 AND COMPANY = 'XYZ'
)
UPDATE PROCESS ... WHERE STATUS = 1 AND COMPANY = 'XYZ'

My question is: is this the most efficient way to do this within T-SQL - or should I be creating some sort of CTE to reference only once? (The number of documents/performance are not a problem, I'm just trying to find out if as an ex OO developer coming to SQL, I'm slipping into bad habits or missing a trick somewhere

Answer 1

I don't think you will be able to use CTE as CTE can be referenced only once. Updating 3 tables requires 3 separate queries to be run.

If obtaining the ID's in your inner query is expensive, you may consider running the query to get them only once and storing the results in a temporary table or table variable. This way you will be able to reference that temporary table or table variable in all update statements.

If the inner query is inexpensive to run, I would leave it as is to not complicate things unnecessarily.