use table alias/name when building date query

use the received table name & table alias arguments in the `get_sql` function to set those as properties on the Date class.

Then, when building the SQL query, use the alias or name (only if available) to prepend to the column name in the query.

This prevents and fixes the issue described in awesomemotive/easy-digital-downloads#9699

src/Database/Queries/Date.php

@@ -152,6 +152,19 @@ class Date extends Base {
 		'AND'
 	);
 
+
+	/**
+	 * @since 3.2.6
+	 * @var string|null Table name
+	 */
+	public $table_name = null;
+
+	/**
+	 * @since 3.2.6
+	 * @var string|null Table alias
+	 */
+	public $table_alias = null;
+
 	/**
 	 * Constructor.
 	 *
@@ -388,6 +401,12 @@ public function get_column( $query = array() ) {
 			? esc_sql( $this->validate_column( $query['column'] ) )
 			: $this->column;
 
+		if (!empty($this->table_alias)) {
+			$retval = $this->table_alias . '.' . $retval;
+		} elseif (!empty($this->table_name)) {
+			$retval = $this->table_name . '.' . $retval;
+		}
+
 		return $retval;
 	}
 
@@ -645,8 +664,10 @@ public function validate_column( $column = '' ) {
 	 *
 	 * @return string MySQL WHERE clauses.
 	 */
-	public function get_sql() {
-		$sql = $this->get_sql_clauses();
+	public function get_sql( $table_name = null, $table_alias = null ) {
+		$this->table_name  = $this->sanitize_table_name( $table_name );
+		$this->table_alias = $this->sanitize_table_name( $table_alias );
+		$sql               = $this->get_sql_clauses();
 
 		/**
 		 * Filters the date query clauses.