Merge pull request #14521 from hexiaoting/dev_like

Add new feature: SHOW DATABASES like 'xxx'

src/Interpreters/InterpreterShowTablesQuery.cpp

@@ -31,7 +31,24 @@ String InterpreterShowTablesQuery::getRewrittenQuery()
 
     /// SHOW DATABASES
     if (query.databases)
-        return "SELECT name FROM system.databases";
+    {
+        std::stringstream rewritten_query;
+        rewritten_query << "SELECT name FROM system.databases";
+
+        if (!query.like.empty())
+        {
+            rewritten_query
+                << " WHERE name "
+                << (query.not_like ? "NOT " : "")
+                << (query.case_insensitive_like ? "ILIKE " : "LIKE ")
+                << std::quoted(query.like, '\'');
+        }
+
+        if (query.limit_length)
+            rewritten_query << " LIMIT " << query.limit_length;
+
+        return rewritten_query.str();
+    }
 
     /// SHOW CLUSTER/CLUSTERS 
     if (query.clusters)
@@ -41,7 +58,11 @@ String InterpreterShowTablesQuery::getRewrittenQuery()
 
         if (!query.like.empty())
         {
-            rewritten_query << " WHERE cluster " << (query.not_like ? "NOT " : "") << "LIKE " << std::quoted(query.like, '\'');
+            rewritten_query
+                << " WHERE cluster "
+                << (query.not_like ? "NOT " : "")
+                << (query.case_insensitive_like ? "ILIKE " : "LIKE ")
+                << std::quoted(query.like, '\'');
         }
 
         if (query.limit_length)
@@ -85,7 +106,11 @@ String InterpreterShowTablesQuery::getRewrittenQuery()
         rewritten_query << "database = " << std::quoted(database, '\'');
 
     if (!query.like.empty())
-        rewritten_query << " AND name " << (query.not_like ? "NOT " : "") << "LIKE " << std::quoted(query.like, '\'');
+        rewritten_query
+            << " AND name "
+            << (query.not_like ? "NOT " : "")
+            << (query.case_insensitive_like ? "ILIKE " : "LIKE ")
+            << std::quoted(query.like, '\'');
     else if (query.where_expression)
         rewritten_query << " AND (" << query.where_expression << ")";
 

src/Parsers/ASTShowTablesQuery.cpp

@@ -13,29 +13,41 @@ ASTPtr ASTShowTablesQuery::clone() const
     return res;
 }
 
+void ASTShowTablesQuery::formatLike(const FormatSettings & settings) const
+{
+    if (!like.empty())
+        settings.ostr
+            << (settings.hilite ? hilite_keyword : "")
+            << (not_like ? " NOT" : "")
+            << (case_insensitive_like ? " ILIKE " : " LIKE ")
+            << (settings.hilite ? hilite_none : "")
+            << std::quoted(like, '\'');
+}
+
+void ASTShowTablesQuery::formatLimit(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const
+{
+    if (limit_length)
+    {
+        settings.ostr << (settings.hilite ? hilite_keyword : "") << " LIMIT " << (settings.hilite ? hilite_none : "");
+        limit_length->formatImpl(settings, state, frame);
+    }
+}
+
 void ASTShowTablesQuery::formatQueryImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const
 {
     if (databases)
     {
         settings.ostr << (settings.hilite ? hilite_keyword : "") << "SHOW DATABASES" << (settings.hilite ? hilite_none : "");
+        formatLike(settings);
+        formatLimit(settings, state, frame);
+
     }
     else if (clusters)
     {
         settings.ostr << (settings.hilite ? hilite_keyword : "") << "SHOW CLUSTERS" << (settings.hilite ? hilite_none : "");
+        formatLike(settings);
+        formatLimit(settings, state, frame);
 
-        if (!like.empty())
-            settings.ostr
-                << (settings.hilite ? hilite_keyword : "")
-                << (not_like ? " NOT" : "")
-                << (case_insensitive_like ? " ILIKE " : " LIKE ")
-                << (settings.hilite ? hilite_none : "")
-                << std::quoted(like, '\'');
-
-        if (limit_length)
-        {
-            settings.ostr << (settings.hilite ? hilite_keyword : "") << " LIMIT " << (settings.hilite ? hilite_none : "");
-            limit_length->formatImpl(settings, state, frame);
-        }
     }
     else if (cluster)
     {
@@ -51,25 +63,15 @@ void ASTShowTablesQuery::formatQueryImpl(const FormatSettings & settings, Format
             settings.ostr << (settings.hilite ? hilite_keyword : "") << " FROM " << (settings.hilite ? hilite_none : "")
                 << backQuoteIfNeed(from);
 
-        if (!like.empty())
-            settings.ostr
-                << (settings.hilite ? hilite_keyword : "")
-                << (not_like ? " NOT" : "")
-                << (case_insensitive_like ? " ILIKE " : " LIKE ")
-                << (settings.hilite ? hilite_none : "")
-                << std::quoted(like, '\'');
+        formatLike(settings);
 
-        else if (where_expression)
+        if (where_expression)
         {
             settings.ostr << (settings.hilite ? hilite_keyword : "") << " WHERE " << (settings.hilite ? hilite_none : "");
             where_expression->formatImpl(settings, state, frame);
         }
 
-        if (limit_length)
-        {
-            settings.ostr << (settings.hilite ? hilite_keyword : "") << " LIMIT " << (settings.hilite ? hilite_none : "");
-            limit_length->formatImpl(settings, state, frame);
-        }
+        formatLimit(settings, state, frame);
     }
 }
 

src/Parsers/ASTShowTablesQuery.h

@@ -36,6 +36,8 @@ public:
     ASTPtr clone() const override;
 
 protected:
+    void formatLike(const FormatSettings & settings) const;
+    void formatLimit(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const;
     void formatQueryImpl(const FormatSettings & settings, FormatState &, FormatStateStacked) const override;
 };
 

src/Parsers/ParserShowTablesQuery.cpp

@@ -46,6 +46,25 @@ bool ParserShowTablesQuery::parseImpl(Pos & pos, ASTPtr & node, Expected & expec
     if (s_databases.ignore(pos))
     {
         query->databases = true;
+
+        if (s_not.ignore(pos, expected))
+            query->not_like = true;
+
+        if (bool insensitive = s_ilike.ignore(pos, expected); insensitive || s_like.ignore(pos, expected))
+        {
+            if (insensitive)
+                query->case_insensitive_like = true;
+
+            if (!like_p.parse(pos, like, expected))
+                return false;
+        }
+        else if (query->not_like)
+            return false;
+        if (s_limit.ignore(pos, expected))
+        {
+            if (!exp_elem.parse(pos, query->limit_length, expected))
+                return false;
+        }
     }
     else if (s_clusters.ignore(pos))
     {

tests/queries/0_stateless/01470_show_databases_like.reference

@@ -0,0 +1 @@
+test_01470

tests/queries/0_stateless/01470_show_databases_like.sql

@@ -0,0 +1,3 @@
+create database if not exists test_01470;
+show databases like '%01470';
+drop database test_01470;