I am surprised that the parameter is even being handled properly as the first value. I would expect it to expand to something along the lines of: ... in ("1,2,3,4,5,6"). In the past, I have done something like splitting the string into an array, building the parameter list using the x (repetition) operator ("... in (" . join(",", ("?")x$size) . ")..."), and then passing the array to execute. I also think that DBIx::PreQL handles an arrayref properly for building this type of query.

A couple ways I've implemented the actual text to make it a little cleaner. All very subjective. Qualified by I nearly always format my statements with a here-doc:

my $sql = <<EOSQL;

SELECT  something 
FROM    atable 
WHERE   data IN (?)

EOSQL
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1. Using baby cart

   my $sql = <<EOSQL;
   
   SELECT  something 
   FROM    atable 
   WHERE   data IN (@{[join ',', ('?') x $size]})
   
   EOSQL
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2. Using $"

   my $sql = do {
       my @holders = ('?') x $size;
       local $" = ',';
       <<EOSQL;
   
   SELECT  something 
   FROM    atable 
   WHERE   data IN (@holders)
   
   EOSQL
   };
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3. Using sprintf

   my $sql = sprintf <<EOSQL, join ',', ('?') x $size;
   
   SELECT  something 
   FROM    atable 
   WHERE   data IN (%s)
   
   EOSQL
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I've generally been using #2 recently.

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#11929 First ask yourself `How would I do this without a computer?' Then have the computer do it the same way.

Don't do that. Dynamic SQL is bad news.

Every RDBMS has this issue, because stored procedures are not able to use a dynamic list. The way to work this out changes by RDBMS, but all of them are ways it split the values in SQL itself.

Anyway, a simple answer would be to use a recursive CTE to split the values into separate records. Once that is done, IN() or EXISTS can SELECT from the entire CTE.

Here's the basic idea. I quickly looked at mysql functions to write this, but have not tested it at all. Hopefully it shows the basic idea:

WITH RECURSIVE split_csv(x, rest)
 AS (     SELECT SUBSTRING_INDEX(?, ',', 1),    SUBSTRING(?, FROM INST
+R(?, ',') + 1)
UNION ALL SELECT SUBSTRING_INDEX(rest, ',', 1), SUBSTRING(rest, FROM I
+NSTR(?, ',') + 1)
FROM split_csv)
SELECT something FROM atable WHERE data in (SELECT x FROM split_csv);
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