From 216cd83b8ed6da5506d315b643a23f9e7b56b8bc Mon Sep 17 00:00:00 2001
From: Anton Popov <anton@clickhouse.com>
Date: Mon, 6 May 2024 17:53:08 +0000
Subject: [PATCH] fix parsing of CREATE INDEX query

---
 src/Parsers/ParserCreateIndexQuery.cpp        | 46 +++++++++++++++----
 ...03146_create_index_compatibility.reference |  1 +
 .../03146_create_index_compatibility.sql      | 17 +++++++
 3 files changed, 54 insertions(+), 10 deletions(-)
 create mode 100644 tests/queries/0_stateless/03146_create_index_compatibility.reference
 create mode 100644 tests/queries/0_stateless/03146_create_index_compatibility.sql

diff --git a/src/Parsers/ParserCreateIndexQuery.cpp b/src/Parsers/ParserCreateIndexQuery.cpp
index fd2bbbab1778..2fa34696c58f 100644
--- a/src/Parsers/ParserCreateIndexQuery.cpp
+++ b/src/Parsers/ParserCreateIndexQuery.cpp
@@ -17,9 +17,9 @@ bool ParserCreateIndexDeclaration::parseImpl(Pos & pos, ASTPtr & node, Expected
 {
     ParserKeyword s_type(Keyword::TYPE);
     ParserKeyword s_granularity(Keyword::GRANULARITY);
-    ParserToken open(TokenType::OpeningRoundBracket);
-    ParserToken close(TokenType::ClosingRoundBracket);
-    ParserOrderByExpressionList order_list;
+    ParserToken open_p(TokenType::OpeningRoundBracket);
+    ParserToken close_p(TokenType::ClosingRoundBracket);
+    ParserOrderByExpressionList order_list_p;
 
     ParserDataType data_type_p;
     ParserExpression expression_p;
@@ -29,17 +29,41 @@ bool ParserCreateIndexDeclaration::parseImpl(Pos & pos, ASTPtr & node, Expected
     ASTPtr type;
     ASTPtr granularity;
 
-    /// Skip name parser for SQL-standard CREATE INDEX
-    if (expression_p.parse(pos, expr, expected))
+    if (open_p.ignore(pos, expected))
     {
-    }
-    else if (open.ignore(pos, expected))
-    {
-        if (!order_list.parse(pos, expr, expected))
+        ASTPtr order_list;
+        if (!order_list_p.parse(pos, order_list, expected))
+            return false;
+
+        if (!close_p.ignore(pos, expected))
             return false;
 
-        if (!close.ignore(pos, expected))
+        if (order_list->children.empty())
             return false;
+
+        /// CREATE INDEX with ASC, DESC is implemented only for SQL compatibility.
+        /// ASC and DESC modifiers are not supported and are ignored further.
+        if (order_list->children.size() == 1)
+        {
+            auto order_by_elem = order_list->children[0];
+            expr = order_by_elem->children[0];
+        }
+        else
+        {
+            auto tuple_func = makeASTFunction("tuple");
+            tuple_func->arguments = std::make_shared<ASTExpressionList>();
+
+            for (const auto & order_by_elem : order_list->children)
+            {
+                auto elem_expr = order_by_elem->children[0];
+                tuple_func->arguments->children.push_back(std::move(elem_expr));
+            }
+            expr = std::move(tuple_func);
+        }
+    }
+    else if (!expression_p.parse(pos, expr, expected))
+    {
+        return false;
     }
 
     if (s_type.ignore(pos, expected))
@@ -59,7 +83,9 @@ bool ParserCreateIndexDeclaration::parseImpl(Pos & pos, ASTPtr & node, Expected
     index->part_of_create_index_query = true;
 
     if (granularity)
+    {
         index->granularity = granularity->as<ASTLiteral &>().value.safeGet<UInt64>();
+    }
     else
     {
         auto index_type = index->getType();
diff --git a/tests/queries/0_stateless/03146_create_index_compatibility.reference b/tests/queries/0_stateless/03146_create_index_compatibility.reference
new file mode 100644
index 000000000000..64f1d1382ee1
--- /dev/null
+++ b/tests/queries/0_stateless/03146_create_index_compatibility.reference
@@ -0,0 +1 @@
+CREATE TABLE default.t_index_3146\n(\n    `a` UInt64,\n    `b` UInt64,\n    INDEX i1 a TYPE minmax GRANULARITY 1,\n    INDEX i2 (a, b) TYPE minmax GRANULARITY 1,\n    INDEX i3 (a, b) TYPE minmax GRANULARITY 1,\n    INDEX i4 a TYPE minmax GRANULARITY 1\n)\nENGINE = MergeTree\nORDER BY tuple()\nSETTINGS index_granularity = 8192
diff --git a/tests/queries/0_stateless/03146_create_index_compatibility.sql b/tests/queries/0_stateless/03146_create_index_compatibility.sql
new file mode 100644
index 000000000000..ede5bc0567a7
--- /dev/null
+++ b/tests/queries/0_stateless/03146_create_index_compatibility.sql
@@ -0,0 +1,17 @@
+DROP TABLE IF EXISTS t_index_3146;
+
+CREATE TABLE t_index_3146 (a UInt64, b UInt64) ENGINE = MergeTree ORDER BY tuple();
+
+SET allow_create_index_without_type = 1;
+
+CREATE INDEX i1 ON t_index_3146 (a) TYPE minmax;
+CREATE INDEX i2 ON t_index_3146 (a, b) TYPE minmax;
+CREATE INDEX i3 ON t_index_3146 (a DESC, b ASC) TYPE minmax;
+CREATE INDEX i4 ON t_index_3146 a TYPE minmax;
+CREATE INDEX i5 ON t_index_3146 (a); -- ignored
+CREATE INDEX i6 ON t_index_3146 (a DESC, b ASC); -- ignored
+CREATE INDEX i7 ON t_index_3146; -- { clientError SYNTAX_ERROR }
+CREATE INDEX i8 ON t_index_3146 a, b TYPE minmax; -- { clientError SYNTAX_ERROR }
+
+SHOW CREATE TABLE t_index_3146;
+DROP TABLE t_index_3146;