[JAVA] How to create a placeholder part to use in the IN clause


There are times when you want to dynamically create the conditional part of SQL. Specifically, when the value set in the IN clause changes dynamically.

SELECT foo FROM sample_table
WHERE bar IN (?, ?, ?, ?, ?); --Here?I want to deal with when the number of

Such SQL is prone to performance issues, but it's often acceptable for small projects. I have an image of a problem that comes when I forget it, and I can write it by using the for statement honestly, but I'd like to write it concisely.

Java implementation

int size = 10; //I want to create?Number of
String placeholders = IntStream.range(0, size)
                               .map(i -> "?")
                               .collect(Collectors.joining(", ", "(", ")"));
// (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)

in conclusion

Personally, if I find an innovative writing style (in each language), I would like to add it.

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