FIX: SQLDescribeParam Causes Syntax Error or Access Violation (293790)

MORE INFORMATION

Calling SQLDescribeParam to obtain information for parameter markers inside a subquery is unsupported. However, if you have a parameter marker after a subquery and you call SQLDescribeParam for that parameter, you will receive the above errors.

Steps to Reproduce Behavior

1. Create a new Win32 console application and add the following code to it:

   #include <windows.h>
         #include <stdio.h>
         #include <sql.h>
         #include <sqlext.h>
   
         void main()
         {
         HENV              henv;
         HDBC              hdbc;
         HSTMT             hstmt;
         SQLRETURN         sr;
   
         SQLCHAR*          theDiagState = new SQLCHAR[50];
         SQLINTEGER        theNativeState;
         SQLCHAR*          theMessageText  = new SQLCHAR[255];
         SQLSMALLINT       iOutputNo,DataType,DecimalDigits, Nullable;
         SQLUINTEGER       ParamSize;
   
         SQLAllocHandle( SQL_HANDLE_ENV, SQL_NULL_HANDLE, & henv );
   
         sr = SQLSetEnvAttr( henv, SQL_ATTR_ODBC_VERSION, ( void * ) SQL_OV_ODBC3, 0 ); 
   
         sr = SQLAllocHandle( SQL_HANDLE_DBC, henv, & hdbc );
   
       
         //Note that the DSN name is Pubs here. Change the DSN name,  
         //user ID, and password here.
         sr = SQLConnect( hdbc, ( unsigned char * ) "Pubs", SQL_NTS, 
      		       ( unsigned char * ) "sa", SQL_NTS, 
      		       ( unsigned char * ) "", SQL_NTS );
   
         sr = SQLAllocHandle( SQL_HANDLE_STMT, hdbc, & hstmt );
      
         //COMMENT THIS LINE AFTER YOU GET THE ERROR.
         sr = SQLPrepare(hstmt,( unsigned char * ) "select A.fname  from employee A where (A.job_id IN (select B.Job_id from jobs B)) AND job_lvl=?", SQL_NTS );<BR/>
       
        //UNCOMMENT THE FOLLOWING LINE TO SEE THE CODE WITHOUT ERROR.
        //This query is equivalent to the one above, but it has the parameter      //marker before the subquery.
        //sr = SQLPrepare(hstmt,( unsigned char * ) "select A.fname  from employee A where job_lvl=? AND (A.job_id IN (select B.Job_id from jobs B)) ", SQL_NTS );
   
         sr = SQLDescribeParam(hstmt,1, &DataType, &ParamSize, &DecimalDigits, &Nullable);
   
   	
         if (sr != SQL_SUCCESS)
         {
              //With this bug, you will get an error message. Check this message in theMessageText.
   
             SQLGetDiagRec(SQL_HANDLE_STMT, hstmt,1,theDiagState, &theNativeState, theMessageText, 100, &iOutputNo);
        
   	 printf( "Error :%s\n", theMessageText);
         }
   	  
         if (sr == SQL_SUCCESS)
         {
   	   printf( "SQLDescribeparam was successful\n");
         }
   
         //Free allocated memory and disconnect.
         SQLFreeStmt( hstmt, SQL_CLOSE );
         SQLFreeStmt( hstmt, SQL_DROP );
         SQLDisconnect( hdbc ); 
         SQLFreeHandle( SQL_HANDLE_DBC, hdbc ); 
         SQLFreeHandle( SQL_HANDLE_ENV, henv );
         delete theMessageText; 
         delete theDiagState;
   
         }
   					

2. Change the data source name (DSN), user ID, and password.
3. Run the code and you will see the error message.
4. Comment the SQLPrepare call, uncomment the call to SQLPrepare that has the parameter marker before the subquery, and then run the code.