fix: fix case issue

tests/system-test/2-query/stbJoin.py

@@ -103,7 +103,7 @@ class TDTestCase:
         tdSql.query(f"select /*+ no_batch_scan() */ count(*) from sta a, stb b where a.tg1=b.tg1 and a.ts=b.ts and b.tg2 > 'a' interval(1a);")
         tdSql.checkRows(3)
 
-        tdSql.query(f"select a.ts, b.ts from sta a, stb b where a.ts=b.ts and (a.t0=b.t0 and a.t0 > b.t0);")
+        tdSql.query(f"select a.ts, b.ts from sta a, stb b where a.ts=b.ts and (a.tg1=b.tg1 and a.tg1 > b.tg1);")
         tdSql.checkRows(0)
 
 #        tdSql.checkData(0,1,10)