why the post queried from sql is more than those showed on the page?

mysql> select count(*) from wp_137_posts where post_type=’post’;
+———-+
| count(*) |
+———-+
| 32 |
+———-+
1 row in set (0.46 sec)

here i find there is 32 posts to the blog whose id is 137

but in fact when i open that blog, i can find only 30 posts include both published and draft.

why there are not 32 posts when i open my blog?