[Core: Candidate] Fix getFirstVisit method

php/libraries/Candidate.class.inc

@@ -625,9 +625,9 @@ class Candidate
         $query  = "SELECT Visit_label
             FROM session s JOIN candidate c ON (c.CandID = s.CandID)
             WHERE c.CandID=:cid AND Date_Visit IS NOT NULL
-            ORDER BY Date_Visit";
+            ORDER BY Date_Visit LIMIT 1";
         $where  = array('cid' => $candID);
-        $vLabel = $db->pselectOne($query, $where);
+        $vLabel = $db->pselectOne($query, $where, false);
 
         return $vLabel;
     }

php/libraries/Database.class.inc

@@ -749,17 +749,27 @@ class Database
     /**
      * Runs a query as a prepared statement and returns the first row as an
      * associative array. Automatically adds a limit clause to the query being
-     * run for efficiency.
+     * run for efficiency. Limit clause can be disabled by setting false as
+     * the third argument.
      *
-     * @param string $query  The SQL SELECT query to be run
-     * @param array  $params Values to use for binding to prepared statement
+     * @param string $query           The SQL SELECT query to be run
+     * @param array  $params          Values to use for binding to prepared
+     *                                statement
+     * @param bool   $efficiencyLimit Determines whether to use LIMIT clause or not
      *
      * @return ?array Associative array of form ColumnName => Value for each column
      *                in the first row of the query
      */
-    function pselectRow(string $query, array $params) : ?array
-    {
-        $rows = $this->pselect($query . " LIMIT 2", $params);
+    function pselectRow(
+        string $query,
+        array $params,
+        bool $efficiencyLimit = true
+    ) : ?array {
+
+        if ($efficiencyLimit) {
+            $query .= " LIMIT 2";
+        }
+        $rows = $this->pselect($query, $params);
         if (count($rows) > 1) {
             throw new \DomainException(
                 "Attempt to use pselectRow on a query that returns multiple rows"
@@ -882,14 +892,17 @@ class Database
      * Runs a query as a prepared statement and returns the value of the first
      * column of the first row
      *
-     * @param string $query  The SQL statement to run
-     * @param array  $params Values to use for binding in the prepared statement
+     * @param string $query           The SQL statement to run
+     * @param array  $params          Values to use for binding in the prepared
+     *                                statement
+     * @param bool   $efficiencyLimit Determines whether to use LIMIT clause in
+     *                                pselectRow
      *
      * @return mixed The value returned by the query.
      */
-    function pselectOne($query, $params)
+    function pselectOne($query, $params, $efficiencyLimit = true)
     {
-        $result = $this->pselectRow($query, $params);
+        $result = $this->pselectRow($query, $params, $efficiencyLimit);
         if (is_array($result) && count($result)) {
             $result = array_values($result)[0];
         }