server/src/api/analytics/utils/getFilterStatement.ts (1)

102-121: ⚠️ Potential issue | 🔴 Critical

Fix regex filter handling in buildSessionLevelSubquery.

filterTypeToOperator() returns null for regex/not_regex, but buildSessionLevelSubquery uses this value directly without checking (line 111). When regex filters are applied to session-level parameters (event_name or channel), the generated SQL becomes malformed: channel null 'pattern'.

The session-level check (line 132) executes before the regex handling logic (line 240), so regex filters never reach the proper match() function implementation. This is a pre-existing bug for event_name that now extends to channel after it was added to DEFAULT_SESSION_LEVEL_PARAMS.

Proposed fix to handle regex in session-level subqueries

   const buildSessionLevelSubquery = (
     param: FilterParameter,
     filterType: FilterType,
     values: (string | number)[],
     wildcardPrefix: string
   ): string => {
+    // Handle regex filters separately using match() function
+    if (filterType === "regex" || filterType === "not_regex") {
+      const pattern = String(values[0] ?? "");
+      const whereClause = [siteIdFilter, timeFilter].filter(Boolean).join(" AND ");
+      const matchExpr = `match(${param}, ${SqlString.escape(pattern)})`;
+      const condition = filterType === "regex" ? matchExpr : `NOT ${matchExpr}`;
+      const finalWhere = whereClause ? `WHERE ${whereClause} AND ${condition}` : `WHERE ${condition}`;
+      return `session_id IN (
+              SELECT DISTINCT session_id
+              FROM events
+              ${finalWhere}
+            )`;
+    }
+
     const whereClause = [siteIdFilter, timeFilter].filter(Boolean).join(" AND ");

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@server/src/api/analytics/utils/getFilterStatement.ts` around lines 102 - 121,
buildSessionLevelSubquery currently uses filterTypeToOperator() directly which
returns null for regex/not_regex causing malformed SQL (e.g., "channel null
'pattern'"); change it to detect regex/not_regex and delegate to the existing
match(...) helper instead of using filterTypeToOperator() for those cases.
Specifically, inside buildSessionLevelSubquery, when filterType is "regex" or
"not_regex" build the condition by calling match(param, value, filterType ===
"not_regex") for each value (and OR-join multiple values) rather than using
filterTypeToOperator, so session-level params like event_name and channel (from
DEFAULT_SESSION_LEVEL_PARAMS) produce correct SQL fragments handled the same way
as other regex logic elsewhere.