fix(sql): keep GaussDB merge actions in statement range

apps/desktop/src/lib/sql/sqlStatementRanges.ts

@@ -803,6 +803,10 @@ function splitStatementRangeAtSoftStarts(sql: string, statement: RawStatement, d
       continue;
     }
 
+    if (currentBodyKeyword === "MERGE" && isMergeActionContinuation(sql, statement.from, lineStart.from, lineStart.keyword, databaseType, parameterOptions)) {
+      continue;
+    }
+
     if (currentBodyKeyword === "ALTER" && isClickHouseAlterTableUpdateContinuation(sql, boundaries[boundaries.length - 1].from, lineStart.from, lineStart.keyword, databaseType)) {
       // ClickHouse mutations use UPDATE as the first ALTER TABLE action, not as
       // a standalone statement. Keep this dialect-specific to preserve soft boundaries elsewhere.
@@ -1068,6 +1072,12 @@ function isMysqlAlterTableTruncatePartitionContinuation(sql: string, statementFr
   return nextSqlWord(sql, lineStartFrom + keyword.length, databaseType) === "PARTITION";
 }
 
+function isMergeActionContinuation(sql: string, statementFrom: number, lineStartFrom: number, keyword: string, databaseType?: DatabaseType, parameterOptions?: SqlParameterOptions): boolean {
+  if (keyword !== "INSERT" || !startsWithSqlWords(sql, statementFrom, ["MERGE"], databaseType, parameterOptions)) return false;
+  const words = topLevelWordsBefore(sql, statementFrom, lineStartFrom, 5, databaseType, parameterOptions);
+  return words[words.length - 1] === "THEN" && words.includes("WHEN") && words.includes("MATCHED");
+}
+
 function startsWithMysqlCreateTable(sql: string, statementFrom: number): boolean {
   const text = sql.slice(statementFrom, statementFrom + 256);
   return /^CREATE\s+(?:TEMPORARY\s+)?TABLE\b/i.test(text);