message: correct handling of NULL for sqlite tests
diff: @@ -82,7 +82,7 @@ duckdbQuery(void *pConn, /* Connection created by xConnect */
  switch (actual_column.type) {
  case DUCKDB_TYPE_TINYINT: {
  - if (0) {
  + if (duckdb_value_is_null(actual_column, r)) {
  snprintf(buffer, BUFSIZ, "%s", "NULL");
  } else {
  snprintf(buffer, BUFSIZ, "%d",
  @@ -91,7 +91,7 @@ duckdbQuery(void *pConn, /* Connection created by xConnect */
  break;
  }
  case DUCKDB_TYPE_SMALLINT: {
  - if (0) {
  + if (duckdb_value_is_null(actual_column, r)) {
  snprintf(buffer, BUFSIZ, "%s", "NULL");
  } else {
  snprintf(buffer, BUFSIZ, "%d",
  @@ -100,7 +100,7 @@ duckdbQuery(void *pConn, /* Connection created by xConnect */
  break;
  }
  case DUCKDB_TYPE_INTEGER: {
  - if (0) {
  + if (duckdb_value_is_null(actual_column, r)) {
  snprintf(buffer, BUFSIZ, "%s", "NULL");
  } else {
  snprintf(buffer, BUFSIZ, "%d",
  @@ -109,7 +109,7 @@ duckdbQuery(void *pConn, /* Connection created by xConnect */
  break;
  }
  case DUCKDB_TYPE_BIGINT: {
  - if (0) {
  + if (duckdb_value_is_null(actual_column, r)) {
  snprintf(buffer, BUFSIZ, "%s", "NULL");
  } else {
  snprintf(buffer, BUFSIZ, "%d",
  @@ -118,7 +118,7 @@ duckdbQuery(void *pConn, /* Connection created by xConnect */
  break;
  }
  case DUCKDB_TYPE_DECIMAL: {
  - if (0) {
  + if (duckdb_value_is_null(actual_column, r)) {
  snprintf(buffer, BUFSIZ, "%s", "NULL");
  } else {
  snprintf(buffer, BUFSIZ, "%lf",
  