diff --git a/core/modules/migrate/src/Plugin/migrate/source/SqlBase.php b/core/modules/migrate/src/Plugin/migrate/source/SqlBase.php
index 214a599ab1..ae219be893 100644
--- a/core/modules/migrate/src/Plugin/migrate/source/SqlBase.php
+++ b/core/modules/migrate/src/Plugin/migrate/source/SqlBase.php
@@ -29,11 +29,12 @@
  *   joined. Using expressions in the query may result in column aliases in the
  *   JOIN clause which would be invalid SQL. If you run into this, set
  *   ignore_map to TRUE.
- * - conditions: (optional) Conditions that should be included in the query.
+ * - conditions: (optional) Conditions to add to the query.
  *   This should be in array format with each array item providing values for
  *   field, value (optional) and operator (optional). Defaults to an empty
  *   array. If value is not defined, defaults to NULL. If operator is not
  *   defined, defaults to '='.
+ *
  *   Example:
  *   @code
  *   source:
@@ -131,7 +132,7 @@ public function __construct(array $configuration, $plugin_id, $plugin_definition
     // Verify conditions configuration.
     $this->configuration['conditions'] = $this->configuration['conditions'] ?? [];
     if (!is_array($this->configuration['conditions'])) {
-      throw new \InvalidArgumentException('Source "conditions" should be an array of conditions including field, value (optional), and operator (optional) values.');
+      throw new \InvalidArgumentException('Source 'conditions' should be an array of conditions including field, value (optional), and operator (optional) values.');
     }
     foreach ($this->configuration['conditions'] as $condition) {
       if (!is_array($condition) || !isset($condition['field'])) {
@@ -141,7 +142,7 @@ public function __construct(array $configuration, $plugin_id, $plugin_definition
     // Verify joins configuration.
     $this->configuration['joins'] = $this->configuration['joins'] ?? [];
     if (!is_array($this->configuration['joins'])) {
-      throw new \InvalidArgumentException('Source "joins" should be an array of conditions including table, alias and condition.');
+      throw new \InvalidArgumentException('Source 'joins' should be an array of conditions including table, alias and condition.');
     }
     foreach ($this->configuration['joins'] as $join) {
       if (!is_array($join) || !isset($join['table']) || !isset($join['alias']) || !isset($join['condition'])) {
@@ -272,10 +273,10 @@ protected function select($table, $alias = NULL, array $options = []) {
   }
 
   /**
-   * Adds tags, metadata, and conditions to the query.
+   * Adds tags, metadata, and configured conditions and joins to the query.
    *
    * @return \Drupal\Core\Database\Query\SelectInterface
-   *   The query with additional tags, metadata, and conditions.
+   *   The query with additional tags, metadata, and configured conditions and joins.
    */
   protected function prepareQuery() {
     $this->query = clone $this->query();
@@ -283,12 +284,12 @@ protected function prepareQuery() {
     $this->query->addTag('migrate_' . $this->migration->id());
     $this->query->addMetaData('migration', $this->migration);
 
-    // Add conditions to the query.
+    // Add any configured conditions.
     foreach ($this->configuration['conditions'] as $condition) {
       $this->query->condition($condition['field'], $condition['value'] ?? NULL, $condition['operator'] ?? '=');
     }
 
-    // Add joins to the query.
+    // Add any configured conditions.
     foreach ($this->configuration['joins'] as $join) {
       $this->query->join($join['table'], $join['alias'], $join['condition']);
     }