[statistics] Fix join ordering; renames and comments

1 files changed, 20 insertions, 3 deletions

diff --git a/modules-available/statistics/inc/hardwarequerycolumn.inc.php b/modules-available/statistics/inc/hardwarequerycolumn.inc.php
index 71793008..d073530b 100644
--- a/modules-available/statistics/inc/hardwarequerycolumn.inc.php
+++ b/modules-available/statistics/inc/hardwarequerycolumn.inc.php
@@ -11,6 +11,7 @@ class HardwareQueryColumn
 	private $alias;
 	private $conditions = [];
 	private $params = [];
+	private $classId;
 
 	private static function getId(): string
 	{
@@ -19,13 +20,19 @@ class HardwareQueryColumn
 
 	public function __construct(bool $global, string $column, string $alias = null)
 	{
+		$this->classId = ++self::$id;
 		$this->global = $global;
 		$this->tableAlias = self::getId();
 		$this->virtualColumnName = $column;
 		$this->alias = $alias ?? $column;
 	}
 
-	public function generate(array &$joins, array &$columns, array &$params)
+	/**
+	 * Add necessary conditions, joins, columns to final SQL arrays. To be called
+	 * from HardwareQuery::buildQuery().
+	 * @param bool $groupConcat whether to add distinct GROUP_CONCAT to column.
+	 */
+	public function generate(array &$joins, array &$columns, array &$params, bool $groupConcat)
 	{
 		if ($this->global) {
 			$srcTable = 'shw';
@@ -46,7 +53,11 @@ class HardwareQueryColumn
 		// INNER JOIN, so the result will be empty if the condition doesn't match.
 		$type = count($this->conditions) === 1 ? 'LEFT' : 'INNER';
 		$joins[] = "$type JOIN $table $tid ON (" . implode(' AND ', $this->conditions) . ")";
-		$columns[] = "$tid.`value` AS `{$this->alias}`";
+		if ($groupConcat) {
+			$columns[] = "Group_Concat(DISTINCT $tid.`value` SEPARATOR ', ') AS `{$this->alias}`";
+		} else {
+			$columns[] = "$tid.`value` AS `{$this->alias}`";
+		}
 		$params += $this->params;
 	}
 
@@ -60,7 +71,13 @@ class HardwareQueryColumn
 	{
 		$valueCol = ($op === '<' || $op === '>' || $op === '<=' || $op === '>=') ? 'numeric' : 'value';
 		if ($other instanceof HardwareQueryColumn) {
-			$this->conditions[] = "{$this->tableAlias}.`$valueCol` $op {$other->tableAlias}.`$valueCol`";
+			$cond = "{$this->tableAlias}.`$valueCol` $op {$other->tableAlias}.`$valueCol`";
+			// Don't reference a column of a table that hasn't been joined yet
+			if ($this->classId > $other->classId) {
+				$this->conditions[] = $cond;
+			} else {
+				$other->conditions[] = $cond;
+			}
 		} else {
 			$pid = self::getId();
 			$this->conditions[] = "{$this->tableAlias}.`$valueCol` $op (:$pid)";