Zabbix

.......PS. [ZBXNEXT-5626] code style changes

* commit '8424b6a813be5fce670c1778ad4c4a965ded2a20':
  .......PS. [ZBXNEXT-5626] sql queries style changes
  .......PS. [ZBXNEXT-5626] removed redundant empty line
  .......PS. [ZBXNEXT-5626] changed database queries formatting
  .......PS. [ZBXNEXT-5626] define functions only if they are being used for specific database engine

(cherry picked from commit 45ce2dd667d7cd7e6497f706ff82855d9a87f877)
(cherry picked from commit 4379b86f16310c0410adf920cce3d5b6ca167c66)