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Asked: 2026-05-11T23:57:28+00:00

I am trying some way to optimize following sql statement: exe_sql DELETE FROM tblEvent_type

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I am trying some way to optimize following sql statement: 

exe_sql "DELETE FROM tblEvent_type WHERE eguid in (SELECT rowid FROM tblEvent_basic WHERE sguid=11);";
exe_sql "DELETE FROM tblEvent_group WHERE eguid in (SELECT rowid FROM tblEvent_basic WHERE sguid=11);";

It is said that sqlite3 did not perform well in subquery and notice that above two sql excuted “(SELECT rowid FROM tblEvent_basic WHERE sguid=11)”` twice ,so I’d like to try to split the subquery to something like below:

result =  exe_sql "(SELECT rowid FROM tblEvent_basic WHERE sguid=11);";
          exe_sql "DELETE FROM tblEvent_type WHERE eguid in  (result)
          exe_sql "DELETE FROM tblEvent_group WHERE eguid in (result)

How could achieve this? I have no idea how to get the parmater (result) binding to follwing statment in sqlite.

"DELETE FROM tblEvent_group WHERE eguid in (?) #how to bind result here

I am using sqlite3 C API directly.

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1 Answer

  1. Editorial Team

    You actually need Common Table Expressions (CTE), but that’s not supported in SQLite.

    Another option would be to store the result of the first query in a temporary table and then use that table in both delete statements:

    CREATE TEMP TABLE items AS SELECT rowid FROM tblEvent_basic WHERE sguid=11

DELETE FROM tblEvent_type WHERE eguid in  (select rowid from items)
DELETE FROM tblEvent_group WHERE eguid in (select rowid from items)

DROP TABLE items

    The DROP TABLE is optional, because the table only exists for the duration of the connection to the database.

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