feat(query): support single point interp syntax

source/libs/parser/inc/parAst.h

@@ -127,6 +127,7 @@ SNode* createIntervalWindowNode(SAstCreateContext* pCxt, SNode* pInterval, SNode
 SNode* createFillNode(SAstCreateContext* pCxt, EFillMode mode, SNode* pValues);
 SNode* createGroupingSetNode(SAstCreateContext* pCxt, SNode* pNode);
 SNode* createInterpTimeRange(SAstCreateContext* pCxt, SNode* pStart, SNode* pEnd);
+SNode* createInterpTimePoint(SAstCreateContext* pCxt, SNode* pPoint);
 SNode* createWhenThenNode(SAstCreateContext* pCxt, SNode* pWhen, SNode* pThen);
 SNode* createCaseWhenNode(SAstCreateContext* pCxt, SNode* pCase, SNodeList* pWhenThenList, SNode* pElse);
 

source/libs/parser/inc/sql.y

@@ -1095,6 +1095,8 @@ having_clause_opt(A) ::= HAVING search_condition(B).
 range_opt(A) ::= .                                                                { A = NULL; }
 range_opt(A) ::=
   RANGE NK_LP expr_or_subquery(B) NK_COMMA expr_or_subquery(C) NK_RP.             { A = createInterpTimeRange(pCxt, releaseRawExprNode(pCxt, B), releaseRawExprNode(pCxt, C)); }
+range_opt(A) ::=
+  RANGE NK_LP expr_or_subquery(B) NK_RP.                                          { A = createInterpTimePoint(pCxt, releaseRawExprNode(pCxt, B)); }
 
 every_opt(A) ::= .                                                                { A = NULL; }
 every_opt(A) ::= EVERY NK_LP duration_literal(B) NK_RP.                           { A = releaseRawExprNode(pCxt, B); }

source/libs/parser/src/parAstCreater.c

@@ -684,6 +684,11 @@ SNode* createInterpTimeRange(SAstCreateContext* pCxt, SNode* pStart, SNode* pEnd
   return createBetweenAnd(pCxt, createPrimaryKeyCol(pCxt, NULL), pStart, pEnd);
 }
 
+SNode* createInterpTimePoint(SAstCreateContext* pCxt, SNode* pPoint) {
+  CHECK_PARSER_STATUS(pCxt);
+  return createOperatorNode(pCxt, OP_TYPE_EQUAL, createPrimaryKeyCol(pCxt, NULL), pPoint);
+}
+
 SNode* createWhenThenNode(SAstCreateContext* pCxt, SNode* pWhen, SNode* pThen) {
   CHECK_PARSER_STATUS(pCxt);
   SWhenThenNode* pWhenThen = (SWhenThenNode*)nodesMakeNode(QUERY_NODE_WHEN_THEN);