Question

the scripts i’ve been working with in SQL work with close to 40,000 records and i’ve noticed a huge increase in execution time for when i use an UPDATE command

in 2 tables that have like 10 fields in them each, INSERT executes quicker for both combined than this UPDATE command

UPADTE table1
INNER JOIN table2 ON table1.primarykey = table2.primarykey
SET table1.code = table2.code

really what the UPDATE is doing is copying the code from one table to another where the identical records exists, this is because table1 is a staging table between 2 databases while table2 is a possessing table to insert staging table’s data across multiple tables, both tables have the same number of record which is about 40,000

now to me UPDATE should be executing a lot quicker, considering it’s only connecting 2 identical tables and inserting data for 1 field it should be running quicker than 2 INSERTS where 40,000 records are being created over 10 fields (so in other words, inserting 800,000 pieces of data) and i’m running the queries in a SQL console windows to avoid php timeouts

is UPDATE somehow more resource hungry than INSERT and is there any way to get it to go faster (apart from changing the fact that i use a separate table for processing, the staging table updates frequently so i copy the data like a snapshot and work with that, the code field is NULL to begin with so i only copy over records with a NULL code meaning records where code is not NULLhave already been worked with)

Answer 1

Is that UPDATE command the actual SQL? Because you need a WHERE clause to avoid updating every record in the table…

Also, INSERT doesn’t first need to find the record to update from 2 joined tables.