[TD-11220]<feature>(query): time related functions

src/common/inc/texpr.h

@@ -71,7 +71,8 @@ struct SSchema;
 #define TSDB_FUNC_SCALAR_TO_ISO8601       (TSDB_FUNC_FLAG_SCALAR | 0x0015)
 #define TSDB_FUNC_SCALAR_TO_UNIXTIMESTAMP (TSDB_FUNC_FLAG_SCALAR | 0x0016)
 #define TSDB_FUNC_SCALAR_TIMETRUNCATE     (TSDB_FUNC_FLAG_SCALAR | 0x0017)
-#define TSDB_FUNC_SCALAR_MAX_NUM      24
+#define TSDB_FUNC_SCALAR_TIMEDIFF         (TSDB_FUNC_FLAG_SCALAR | 0x0018)
+#define TSDB_FUNC_SCALAR_MAX_NUM      25
 
 #define TSDB_FUNC_SCALAR_NAME_MAX_LEN 16
 

src/common/src/texpr.c

@@ -84,7 +84,8 @@ int32_t exprTreeValidateFunctionNode(char* msgbuf, tExprNode *pExpr) {
     case TSDB_FUNC_SCALAR_TIMEZONE:
     case TSDB_FUNC_SCALAR_TO_ISO8601:
     case TSDB_FUNC_SCALAR_TO_UNIXTIMESTAMP:
-    case TSDB_FUNC_SCALAR_TIMETRUNCATE: {
+    case TSDB_FUNC_SCALAR_TIMETRUNCATE:
+    case TSDB_FUNC_SCALAR_TIMEDIFF: {
       return exprValidateTimeNode(msgbuf, pExpr);
     }
 
@@ -1424,6 +1425,9 @@ int32_t exprValidateTimeNode(char *msgbuf, tExprNode *pExpr) {
       pExpr->resultBytes = (int16_t)tDataTypes[TSDB_DATA_TYPE_TIMESTAMP].bytes;
       break;
     }
+    case TSDB_FUNC_SCALAR_TIMEDIFF: {
+      break;
+    }
     default: {
       assert(false);
       break;
@@ -2124,6 +2128,9 @@ void vectorTimeFunc(int16_t functionId, tExprOperandInfo *pInputs, int32_t numIn
 
           break;
         }
+        case TSDB_FUNC_SCALAR_TIMEDIFF: {
+          break;
+        }
         default: {
           assert(false);
           break;
@@ -2262,4 +2269,9 @@ tScalarFunctionInfo aScalarFunctions[] = {
         "timetruncate",
         vectorTimeFunc
     },
+    {
+        TSDB_FUNC_SCALAR_TIMEDIFF,
+        "timediff",
+        vectorTimeFunc
+    },
 };