[SOLVED] PreparedStatement with list of parameters in a IN clause

PreparedStatement with list of parameters in a IN clause

How to set value for in clause in a preparedStatement in JDBC while executing a query.

Example:

connection.prepareStatement("Select * from test where field in (?)");

If this in-clause can hold multiple values how can I do it. Sometimes I know the list of parameters beforehand or sometimes I don't know beforehand. How to handle this case?

Solution

What I do is to add a "?" for each possible value.

var stmt = String.format("select * from test where field in (%s)",
                         values.stream()
                         .map(v -> "?")
                         .collect(Collectors.joining(", ")));

Alternative using StringBuilder (which was the original answer 10+ years ago)

List values = ... 
StringBuilder builder = new StringBuilder();

for( int i = 0 ; i < values.size(); i++ ) {
    builder.append("?,");
}

String placeHolders =  builder.deleteCharAt( builder.length() -1 ).toString();
String stmt = "select * from test where field in ("+ placeHolders + ")";
PreparedStatement pstmt = ...

And then happily set the params

int index = 1;
for( Object o : values ) {
   pstmt.setObject(  index++, o ); // or whatever it applies 
}