Use table alias/name when building date query (#164)

* 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
* Update get_sql params as per WP_Meta_Query
* Update get_column to only use the table_name
* Removed the table alias as that's not something WP_Meta_Query uses

src/Database/Queries/Date.php

@@ -152,6 +152,13 @@ class Date extends Base {
 		'AND'
 	);
 
+
+	/**
+	 * @since 2.0.2
+	 * @var string|null Table name
+	 */
+	public $table_name = null;
+
 	/**
 	 * Constructor.
 	 *
@@ -388,6 +395,10 @@ public function get_column( $query = array() ) {
 			? esc_sql( $this->validate_column( $query['column'] ) )
 			: $this->column;
 
+		if (!empty($this->table_name)) {
+			$retval = $this->table_name . '.' . $retval;
+		}
+
 		return $retval;
 	}
 
@@ -645,8 +656,9 @@ public function validate_column( $column = '' ) {
 	 *
 	 * @return string MySQL WHERE clauses.
 	 */
-	public function get_sql() {
-		$sql = $this->get_sql_clauses();
+	public function get_sql( $type, $primary_table, $primary_id_column, $context = null ) {
+		$this->table_name  = $this->sanitize_table_name( $primary_table );
+		$sql               = $this->get_sql_clauses();
 
 		/**
 		 * Filters the date query clauses.