The 'Data Search' feature lets you find specific data without actually writing any SQL. It is available from the 'file' menu. If you select this menu item a new TAB (named 'Data Search') will open along with the Query/Query Builder/Schema Designer tabs you have opened already. Also the "+" icon to the right of the rightmost tab in the query pane has an option to open a Data Search tab. You may open as many Data Search tabs as you want. A 'Data Search' TAB is 'sticky'. It will have to be closed by the user and only updates when the 'Search' button is clicked. So you can keep it open for as long as you want and can work elsewhere in the program and return to it later.
After entering some text in the text-box, click 'Search' or push enter. SQLyog will find all data that matches the search string entered. The search happens inside the currently selected database/table/column (or globally if the connection/server node is selected). Every row fulfilling the search criteria for just a single column in the currently selected connection/database/table/column will be returned in the result of the search.
Note: This feature is available in SQLyog Ultimate.