Added links to live demos

Enabled by simonw/datasette#761

sqlite/list-all-columns-in-a-database.md

@@ -2,15 +2,15 @@
 
 Here's a devious trick for listing ALL columns in a SQLite database, using a SQL query that generates another SQL query.
 
-The first query:
+The first query ([demo](https://latest.datasette.io/fixtures?sql=select+group_concat%28%0D%0A++%22select+%27%22+%7C%7C+name+%7C%7C+%22%27+as+table_name%2C+*+from+pragma_table_info%28%27%22+%7C%7C+name+%7C%7C+%22%27%29%22%0D%0A%2C+%27+union+%27%29+%7C%7C+%27+order+by+table_name%2C+cid%27%0D%0A++from+sqlite_master+where+type+%3D+%27table%27%3B)):
 
 ```sql
 select group_concat(
   "select '" || name || "' as table_name, * from pragma_table_info('" || name || "')"
 , ' union ') || ' order by table_name, cid'
   from sqlite_master where type = 'table';
 ```
-This outputs the second query, which will look something like this:
+This outputs the second query, which will look something like this ([demo](https://latest.datasette.io/fixtures?sql=select+%27simple_primary_key%27+as+table_name%2C+*+from+pragma_table_info%28%27simple_primary_key%27%29+union+select+%27primary_key_multiple_columns%27+as+table_name%2C+*+from+pragma_table_info%28%27primary_key_multiple_columns%27%29+union+select+%27primary_key_multiple_columns_explicit_label%27+as+table_name%2C+*+from+pragma_table_info%28%27primary_key_multiple_columns_explicit_label%27%29+union+select+%27compound_primary_key%27+as+table_name%2C+*+from+pragma_table_info%28%27compound_primary_key%27%29+union+select+%27compound_three_primary_keys%27+as+table_name%2C+*+from+pragma_table_info%28%27compound_three_primary_keys%27%29+union+select+%27foreign_key_references%27+as+table_name%2C+*+from+pragma_table_info%28%27foreign_key_references%27%29+union+select+%27sortable%27+as+table_name%2C+*+from+pragma_table_info%28%27sortable%27%29+union+select+%27no_primary_key%27+as+table_name%2C+*+from+pragma_table_info%28%27no_primary_key%27%29+union+select+%27123_starts_with_digits%27+as+table_name%2C+*+from+pragma_table_info%28%27123_starts_with_digits%27%29+union+select+%27Table+With+Space+In+Name%27+as+table_name%2C+*+from+pragma_table_info%28%27Table+With+Space+In+Name%27%29+union+select+%27table%2Fwith%2Fslashes.csv%27+as+table_name%2C+*+from+pragma_table_info%28%27table%2Fwith%2Fslashes.csv%27%29+union+select+%27complex_foreign_keys%27+as+table_name%2C+*+from+pragma_table_info%28%27complex_foreign_keys%27%29+union+select+%27custom_foreign_key_label%27+as+table_name%2C+*+from+pragma_table_info%28%27custom_foreign_key_label%27%29+union+select+%27units%27+as+table_name%2C+*+from+pragma_table_info%28%27units%27%29+union+select+%27tags%27+as+table_name%2C+*+from+pragma_table_info%28%27tags%27%29+union+select+%27searchable%27+as+table_name%2C+*+from+pragma_table_info%28%27searchable%27%29+union+select+%27searchable_tags%27+as+table_name%2C+*+from+pragma_table_info%28%27searchable_tags%27%29+union+select+%27searchable_fts%27+as+table_name%2C+*+from+pragma_table_info%28%27searchable_fts%27%29+union+select+%27searchable_fts_content%27+as+table_name%2C+*+from+pragma_table_info%28%27searchable_fts_content%27%29+union+select+%27searchable_fts_segments%27+as+table_name%2C+*+from+pragma_table_info%28%27searchable_fts_segments%27%29+union+select+%27searchable_fts_segdir%27+as+table_name%2C+*+from+pragma_table_info%28%27searchable_fts_segdir%27%29+union+select+%27select%27+as+table_name%2C+*+from+pragma_table_info%28%27select%27%29+union+select+%27infinity%27+as+table_name%2C+*+from+pragma_table_info%28%27infinity%27%29+union+select+%27facet_cities%27+as+table_name%2C+*+from+pragma_table_info%28%27facet_cities%27%29+union+select+%27facetable%27+as+table_name%2C+*+from+pragma_table_info%28%27facetable%27%29+union+select+%27binary_data%27+as+table_name%2C+*+from+pragma_table_info%28%27binary_data%27%29+union+select+%27roadside_attractions%27+as+table_name%2C+*+from+pragma_table_info%28%27roadside_attractions%27%29+union+select+%27attraction_characteristic%27+as+table_name%2C+*+from+pragma_table_info%28%27attraction_characteristic%27%29+union+select+%27roadside_attraction_characteristics%27+as+table_name%2C+*+from+pragma_table_info%28%27roadside_attraction_characteristics%27%29+order+by+table_name%2C+cid)):
 ```sql
 select 'simple_primary_key' as table_name, * from pragma_table_info('simple_primary_key') union
 select 'primary_key_multiple_columns' as table_name, * from pragma_table_info('primary_key_multiple_columns') union