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willsherwood

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mysql DELETE "gets stuck"

I've inherited the following "nested" DELETE query,
where the desire is to delete those records in the Purchase_order_details table that
are referred to in the Sales_order_details  table.

tblPOdetails                           tblSOdetails
po_detail_key    <-------------- po_detail_key
                                                 so_header_key   =   123456  (a specific value when handed to mySQL)

DELETE FROM tblPurchase_order_details       
                        WHERE po_detail_key IN
                              (SELECT po_detail_key FROM tblSales_order_details
                                    WHERE so_header_key='{$SOHID']}'
                              )

The server shows the mySQL state of this query to be          "Sending data"
and it's stuck there until i restart mySQL on the server.

I can unravel the "nested" query to be implemented using a PHP loop, but wondering if there's
a way it can work WITHIN mySQL?

p.s. it's INNODB with no constraints defined,  all other queries work fine.
the design, etc.  had been translated from an ASP/Microsoft implementation from 15+ yrs ago.
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Dave Baldwin
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This '{$SOHID']}' is not a valid anything that I know of.  Please post the actual code in the 'code' format so we can see what you are actually doing.  You can replace any sensitive data but otherwise keep the code as it is found.  Like this...

DELETE FROM tblPurchase_order_details       
                        WHERE po_detail_key IN
                              (SELECT po_detail_key FROM tblSales_order_details
                                    WHERE so_header_key='{$SOHID']}'
                              ) 

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Gary
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willsherwood

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sorry for the copy/paste typo.

the  '{$SOHID}'  is a PHP variable that expands to a literal/constant for the query

i'll try your INNER JOIN now !
super, thanks for your help in translating to use  INNER JOIN - a great help!
p.s.   just curious why something like this would "hang" mySQL for THIS database  when executed
 (other db were operational
during the period that this  query took hold of the the database)
Could be several things without knowing the db setup. But a join is better than a nested select which involves more work.