This tab is displayed only when one of the bulk keys described here is used or when the following key is added to the AppSettings section of your web.config file:
<add key="CMSDebugSQLQueries" value="true"/>
On the Debug -> SQL queries tab, you can see a log of SQL queries called on loading of particular pages. For each record, there is row with a URL of the loaded page followed by its time of display. Below it, you can find a table listing all SQL queries executed when loading the page.
For each query, there are two lines in the table. The first line contains the exact text of the query, while the second line contains the number of loaded rows, columns in each row and the size of the loaded data. The Context column shows where the query was called from. The last column of the table displays the exact duration of query execution. The last line of the table displays the overall page loading time.
Clicking the Clear SQL log button clears all records in this debug log.