YQL-19747: Complete columns at simple select

Added support for a columns completion at a simple select. For example, `` SELECT # FROM hahn.`home/yql/tutorial/users` `` и `` USE hahn; SELECT $ FROM `home/yql/tutorial/users` ``.
commit_hash:2254449e91255c19792a1dc521825e44dda7d63b

1 files changed, 12 insertions, 0 deletions

diff --git a/yql/essentials/sql/v1/complete/sql_complete.cpp b/yql/essentials/sql/v1/complete/sql_complete.cpp
index eea7571e8f1..2f61b1fe4df 100644
--- a/yql/essentials/sql/v1/complete/sql_complete.cpp
+++ b/yql/essentials/sql/v1/complete/sql_complete.cpp
@@ -142,6 +142,11 @@ namespace NSQLComplete {
                 object->Kinds.emplace(EObjectKind::Table);
             }
 
+            if (context.Column && global.Column) {
+                request.Constraints.Column = TColumnName::TConstraints();
+                request.Constraints.Column->Tables = std::move(global.Column->Tables);
+            }
+
             return request;
         }
 
@@ -231,6 +236,10 @@ namespace NSQLComplete {
                     return {ECandidateKind::ClusterName, std::move(name.Indentifier)};
                 }
 
+                if constexpr (std::is_base_of_v<TColumnName, T>) {
+                    return {ECandidateKind::ColumnName, std::move(name.Indentifier)};
+                }
+
                 if constexpr (std::is_base_of_v<TBindingName, T>) {
                     if (!context.Binding) {
                         name.Indentifier.prepend('$');
@@ -333,6 +342,9 @@ void Out<NSQLComplete::ECandidateKind>(IOutputStream& out, NSQLComplete::ECandid
         case NSQLComplete::ECandidateKind::BindingName:
             out << "BindingName";
             break;
+        case NSQLComplete::ECandidateKind::ColumnName:
+            out << "ColumnName";
+            break;
         case NSQLComplete::ECandidateKind::UnknownName:
             out << "UnknownName";
             break;