Preparing Statements That Receive Parameters

The PREPARE statements in the following examples show some uses of question-mark ( ? ) placeholders:

EXEC SQL prepare s3 from
   'select * from customer where state matches ?';
EXEC SQL prepare in1 from 'insert into manufact values (?,?,?)';
sprintf(up_query, "%s %s", 
   "update customer set zipcode = ?"
   "where current of zip_cursor"); 
EXEC SQL prepare update2 from :up_query;
EXEC SQL prepare exfunc from
   'execute function func1 (?, ?)';

The following example of the code fragment prepares a statement from a variable that is named demoquery. The text in the variable includes one question-mark ( ? ) placeholder. The prepared statement is associated with a cursor and, when the cursor is opened, the USING clause of the OPEN statement supplies a value for the placeholder:

EXEC SQL BEGIN DECLARE SECTION;
   char queryvalue [6];
   char demoquery  [80];
EXEC SQL END DECLARE SECTION;

EXEC SQL connect to 'stores_demo';
sprintf(demoquery, "%s %s",
      "select fname, lname from customer ",
      "where lname > ? ");
EXEC SQL prepare quid from :demoquery;
EXEC SQL declare democursor cursor for quid;
stcopy("C", queryvalue);
EXEC SQL open democursor using :queryvalue;