psql: Don't automatically use expanded format when there's 1 column.

Andreas Karlsson and Robert Haas

doc/src/sgml/ref/psql-ref.sgml

@@ -2119,8 +2119,9 @@ lo_import 152801
           column name on the left and the data on the right. This mode is
           useful if the data wouldn't fit on the screen in the
           normal <quote>horizontal</quote> mode.  In the auto setting, the
-          expanded mode is used whenever the query output is wider than the
-          screen, otherwise the regular mode is used.  The auto setting is only
+          expanded mode is used whenever the query output has more than one
+          column and is wider than the screen; otherwise, the regular mode is
+          used.  The auto setting is only
           effective in the aligned and wrapped formats.  In other formats, it
           always behaves as if the expanded mode is off.
           </para>

src/bin/psql/print.c

@@ -816,9 +816,11 @@ print_aligned_text(const printTableContent *cont, FILE *fout, bool is_pager)
 
 	/*
 	 * If in expanded auto mode, we have now calculated the expected width, so
-	 * we can now escape to vertical mode if necessary.
+	 * we can now escape to vertical mode if necessary.  If the output has
+	 * only one column, the expanded format would be wider than the regular
+	 * format, so don't use it in that case.
 	 */
-	if (cont->opt->expanded == 2 && output_columns > 0 &&
+	if (cont->opt->expanded == 2 && output_columns > 0 && cont->ncolumns > 1 &&
 		(output_columns < total_header_width || output_columns < width_total))
 	{
 		print_aligned_vertical(cont, fout, is_pager);