add json compare function support

src/client/src/tscSubquery.c

@@ -722,8 +722,19 @@ int32_t tagValCompar(const void* p1, const void* p2) {
   const STidTags* t2 = (const STidTags*) varDataVal(p2);
 
   if (t1->padding == TSDB_DATA_TYPE_JSON){
-    __compar_fn_t func = getComparFunc(t1->tag[0], 0);
-    return func(t1->tag + CHAR_BYTES, t2->tag + CHAR_BYTES);
+    bool f1IsNull = (*t1->tag == TSDB_DATA_TYPE_NCHAR && isNull(t1->tag + CHAR_BYTES, TSDB_DATA_TYPE_JSON));
+    bool f2IsNull = (*t1->tag == TSDB_DATA_TYPE_NCHAR && isNull(t1->tag + CHAR_BYTES, TSDB_DATA_TYPE_JSON));
+    if(f1IsNull && f2IsNull){
+      return 0;
+    }else if(f1IsNull && !f2IsNull){
+      return -1;
+    }else if(!f1IsNull && f2IsNull){
+      return 1;
+    }else {
+      assert(*t1->tag == *t1->tag);
+      __compar_fn_t func = getComparFunc(t1->tag[0], 0);
+      return func(t1->tag + CHAR_BYTES, t2->tag + CHAR_BYTES);
+    }
   }
   __compar_fn_t func = getComparFunc(t1->padding, 0);
   return func(t1->tag, t2->tag);

src/query/src/qExtbuffer.c

@@ -368,10 +368,20 @@ static int32_t tsCompareFunc(TSKEY k1, TSKEY k2, int32_t order) {
 
 int32_t columnValueAscendingComparator(char *f1, char *f2, int32_t type, int32_t bytes) {
   if (type == TSDB_DATA_TYPE_JSON){
-    assert(*f1 == *f2);
-    type = *f1;
-    f1 = POINTER_SHIFT(f1, CHAR_BYTES);
-    f2 = POINTER_SHIFT(f2, CHAR_BYTES);
+    bool f1IsNull = (*f1 == TSDB_DATA_TYPE_NCHAR && isNull(f1 + CHAR_BYTES, TSDB_DATA_TYPE_JSON));
+    bool f2IsNull = (*f2 == TSDB_DATA_TYPE_NCHAR && isNull(f2 + CHAR_BYTES, TSDB_DATA_TYPE_JSON));
+    if(f1IsNull && f2IsNull){
+      return 0;
+    }else if(f1IsNull && !f2IsNull){
+      return -1;
+    }else if(!f1IsNull && f2IsNull){
+      return 1;
+    }else{
+      assert(*f1 == *f2);
+      type = *f1;
+      f1 += CHAR_BYTES;
+      f2 += CHAR_BYTES;
+    }
   }
   switch (type) {
     case TSDB_DATA_TYPE_INT:     DEFAULT_COMP(GET_INT32_VAL(f1), GET_INT32_VAL(f2));

tests/pytest/stable/json_tag.py

@@ -279,7 +279,7 @@ class TDTestCase:
         tdSql.execute("INSERT INTO db_json_tag_test.jsons1_21 using db_json_tag_test.jsons1 tags('{\"tagint\":11}') values(now, 11, false, \"你就会\")")
         tdSql.execute("INSERT INTO db_json_tag_test.jsons1_22 using db_json_tag_test.jsons1 tags('{\"tagint\":2}') values(now, 2, false, \"你就会\")")
         tdSql.query("select avg(dataint),count(*) from db_json_tag_test.jsons1 group by jtag->'tagint' order by jtag->'tagint' desc")
-        //tdSql.checkData(1, 0, 2.5)
+        #tdSql.checkData(1, 0, 2.5)
 
         # test json->'key'=null
         tdSql.execute("insert into db_json_tag_test.jsons1_9 values('2020-04-17 15:20:00.000', 5, false, 'json19')")