for #2084, add top for sqlserver.g4

sharding-core/sharding-core-parse/sharding-core-parse-sqlserver/src/main/antlr4/imports/sqlserver/DMLStatement.g4

@@ -89,7 +89,11 @@ selectItems
     ;
 
 selectItem
-    : (columnName | expr) (AS? alias)? | qualifiedShorthand
+    : (top | columnName | expr) (AS? alias)? | qualifiedShorthand
+    ;
+
+top
+    : TOP LP_? expr RP_? ROW_NUMBER LP_ RP_ LP_ orderByClause RP_ 
     ;
 
 alias

sharding-core/sharding-core-parse/sharding-core-parse-sqlserver/src/main/antlr4/imports/sqlserver/SQLServerKeyword.g4

@@ -43,6 +43,10 @@ REGEXP
     : R E G E X P
     ;
 
+TOP
+    : T O P
+    ;
+
 ROW
     : R O W
     ;
@@ -538,3 +542,7 @@ LOCK_ESCALATION
 DROP_EXISTING
     : D R O P UL_ E X I S T I N G
     ;
+
+ROW_NUMBER
+    : R O W UL_ N U M B E R
+    ;