$Query = "SELECT * from posts WHERE post_catecory_id = $post_category_id ";

Quote:

Missing Data

Sometimes data can be missing from the database. This causes issues when the data is required for a query to complete. For example, if a database is built requiring an ID number for every student, it is reasonable to assume a query will be built to pull a student record by that ID number. Such a query would look like this:

SQL

SELECT * from students WHERE studentID = $id

If the $id is never properly filled in the code, the query would look like this to the server:

SQL

SELECT * from students WHERE studentID =

Since there is nothing there, the MySQL engine gets confused and complains via a 1064 error.

How to fix it:
Hopefully, your application will have some sort of interface that will allow you to bring up the particular record and add the missing data. This is tricky because if the missing data is the unique identifier, it will likely need that information to bring it up, thus resulting in the same error. You can also go into the database (typically within phpMyAdmin) where you can select the particular row from the appropriate table and manually add the data.