Сергей Водаков

WITH CTE_Hierarchy (id,  parent_id, level, path) 
AS 
(SELECT id, parent_id, 1 ,cast(slug as varchar(100)) as path
    FROM 
        categoryes
    WHERE parent_id IS NULL //Если для пустых parent_id предусмотрено другое значение то поменять условие
    UNION ALL 
       SELECT subcategory.id, subcategory.parent_id, level + 1, 
		case cast(path + '/' + subcategory.slug as varchar(100)) as path
    FROM  categoryes AS subcategory 
INNER JOIN CTE_Hierarchy AS parentHierarchy ON subcategory.parent_id = parentHierarchy.id)

SELECT 
*
FROM logTable
WHERE logTable.date > DATEADD(month, -1, (SELECT MAX(logTable.date) FROM logTable))

DELETE
FROM logTable
WHERE logTable.date <= DATEADD(month, -1, (SELECT MAX(logTable.date) FROM logTable))

LEFT JOIN keywords ON keywords.event_id = events.id