<p>
  Querying an LTPDA repository is done using standard SQL statements. The repository GUI
  presents the user with the possibility to graphically build SQL statements which avoids
  learning SQL syntax. Currently, the SQL statements that can be built in this way are 
  restricted to queries on a single database table. High-level queries, searching more database tables at once, are implemented in the following panel.
</p>
<p>
  The repository GUI has a query panel which looks like the figure below:
</p>
<br>
<br>
<img src="images/repo_gui_query_1.png" alt="Repo GUI Query">
<br>
<br>
<p>
  In this figure, you see that the user has built a query to select all objects 
  submitted on the 24th February 2008. The results will contain the object id, 
  the submitted date, the experiment title, the experiment description, and the analysis
  description. The results will be sorted in descending order of the object id.
</p>
<p>
  Executing the query (click the 'Execute query' button) produces the results table
  shown below.
</p>
<br>
<br>
<img src="images/repo_gui_query_2.png" alt="Repo GUI Query Results">
<br>
<br>
<p>
  The query string that is actually executed is presented in the text edit
  box above the 'Execute query' button. This query string can be edited to allow for finer
  control over the query. This is meant for users who already have a working knowledge of MySQL 
  SQL syntax.
</p>