diff --git a/convert.c b/convert.c
index 0e7bd37..b8fe0f5 100644
--- a/convert.c
+++ b/convert.c
@@ -3727,8 +3727,17 @@ inolog("num_p=%d\n", num_p);
 
 			inolog("%dth parameter type oid is %u\n", i, PIC_dsp_pgtype(conn, parameters[i]));
 
-			if (discard_output && SQL_PARAM_OUTPUT == parameters[i].paramType)
+			if (SQL_PARAM_OUTPUT == parameters[i].paramType)
+			{
+				if (discard_output)
+					continue;
+				(*paramTypes)[*nParams] = PG_TYPE_VOID;
+				(*paramValues)[*nParams] = NULL;
+				(*paramLengths)[*nParams] = 0;
+				(*paramFormats)[*nParams] = 0;
+				(*nParams)++;
 				continue;
+			}
 
 			qb.npos = 0;
 			retval = ResolveOneParam(&qb, NULL, &isnull, &isbinary, &pgType);
@@ -3747,21 +3756,21 @@ inolog("num_p=%d\n", num_p);
 				memcpy(val_copy, qb.query_statement, qb.npos);
 				val_copy[qb.npos] = '\0';
 
-				(*paramTypes)[i] = pgType;
-				(*paramValues)[i] = val_copy;
+				(*paramTypes)[*nParams] = pgType;
+				(*paramValues)[*nParams] = val_copy;
 				if (qb.npos > INT_MAX)
 					goto cleanup;
-				(*paramLengths)[i] = (int) qb.npos;
+				(*paramLengths)[*nParams] = (int) qb.npos;
 			}
 			else
 			{
-				(*paramTypes)[i] = pgType;
-				(*paramValues)[i] = NULL;
-				(*paramLengths)[i] = 0;
+				(*paramTypes)[*nParams] = pgType;
+				(*paramValues)[*nParams] = NULL;
+				(*paramLengths)[*nParams] = 0;
 			}
 			if (isbinary)
 				mylog("%dth parameter is of binary format\n", *nParams);
-			(*paramFormats)[i] = isbinary ? 1 : 0;
+			(*paramFormats)[*nParams] = isbinary ? 1 : 0;
 
 			(*nParams)++;
 		}