#5179 Fixed results returned from query joining the same table twice.

Author: pawelsalawa

ChangeLog.md

@@ -1,5 +1,9 @@
 # ChangeLog
 
+### 3.4.12
+- BIGFIX: #5179 Fixed results returned from query joining the same table twice.
+- BIGFIX: #5179 Fixed smart execution when joining tables with USING clause, so the result metadata is extracted properly and results can be edited.
+
 ### 3.4.11
 - CHANGE: SQLite updated to 3.47.2
 - BUGFIX: #5161 An ultimate fix for dialog windows positioning, so they no longer can appear outside of visible screen.

SQLiteStudio3/coreSQLiteStudio/db/queryexecutorsteps/queryexecutoraddrowids.cpp

@@ -61,7 +61,7 @@ QHash<SelectResolver::Table,QHash<QString,QString>> QueryExecutorAddRowIds::addR
             return rowIdColsMap;
 
     }
-    core->rebuildTokens();
+    select->rebuildTokens();
 
     // Getting all tables we need to get ROWID for
     SelectResolver resolver(db, select->tokens.detokenize(), context->dbNameToAttach);

SQLiteStudio3/coreSQLiteStudio/db/queryexecutorsteps/queryexecutorcolumns.cpp

@@ -69,13 +69,15 @@ bool QueryExecutorColumns::exec()
             context->resultColumns << resultColumn; // store it in context for later usage by any step
     }
 
-//    qDebug() << "before: " << context->processedQuery;
+    //qDebug() << "before: " << context->processedQuery;
     // Update query
     select->rebuildTokens();
-    wrapWithAliasedColumns(select.data());
+    // #5179 does not seem to be needed anymore, because query executor alias is applied always in the main column loop above.
+    // Keeping the commented reference here for a while, but to be removed in future (due to end of 2025).
+    //wrapWithAliasedColumns(select.data());
     updateQueries();
 
-//    qDebug() << "after:  " << context->processedQuery;
+    //qDebug() << "after:  " << context->processedQuery;
 
     return true;
 }
@@ -176,11 +178,13 @@ SqliteSelect::Core::ResultColumn* QueryExecutorColumns::getResultColumnForSelect
         }
     }
 
-    selectResultColumn->asKw = true;
     if (!col.alias.isNull())
-        selectResultColumn->alias = col.alias;
-    else
-        selectResultColumn->alias = resultColumn->queryExecutorAlias;
+        selectResultColumn->expr->column = col.alias;
+
+    // #5179 duplicate of the same source table columns (but with different table alias) requires executor alias to be applied
+    // always and immediately here to get proper results.
+    selectResultColumn->asKw = true;
+    selectResultColumn->alias = resultColumn->queryExecutorAlias;
 
     // If this alias was already used we need to use sequential alias
     static_qstring(aliasTpl, "%1:%2");
@@ -212,63 +216,6 @@ bool QueryExecutorColumns::isRowIdColumnAlias(const QString& alias)
     return false;
 }
 
-void QueryExecutorColumns::wrapWithAliasedColumns(SqliteSelect* select)
-{
-    // Wrap everything in a surrounding SELECT and given query executor alias to all columns this time
-    TokenList sepTokens;
-    sepTokens << TokenPtr::create(Token::OPERATOR, ",") << TokenPtr::create(Token::SPACE, " ");
-
-    bool first = true;
-    TokenList outerColumns;
-    QStringList columnNamesUsed;
-    QString baseColName;
-    QString colName;
-    static_qstring(colNameTpl, "%1:%2");
-    for (QueryExecutor::ResultColumnPtr& resCol : context->resultColumns)
-    {
-        if (!first)
-            outerColumns += sepTokens;
-
-        // If alias was given, we use it. If it was anything but expression, we also use its display name,
-        // because it's explicit column (no matter if from table, or table alias).
-        baseColName = QString();
-        if (!resCol->queryExecutorAlias.isNull())
-            baseColName = resCol->alias;
-        else if (!resCol->expression)
-            baseColName = resCol->column;
-
-        if (!baseColName.isNull())
-        {
-            colName = baseColName;
-            for (int i = 1; columnNamesUsed.contains(colName, Qt::CaseInsensitive); i++)
-                colName = colNameTpl.arg(resCol->column, QString::number(i));
-
-            columnNamesUsed << colName;
-            outerColumns << TokenPtr::create(Token::OTHER, wrapObjIfNeeded(colName));
-            outerColumns << TokenPtr::create(Token::SPACE, " ");
-            outerColumns << TokenPtr::create(Token::KEYWORD, "AS");
-            outerColumns << TokenPtr::create(Token::SPACE, " ");
-        }
-        outerColumns << TokenPtr::create(Token::OTHER, resCol->queryExecutorAlias);
-        first = false;
-    }
-
-    for (QueryExecutor::ResultRowIdColumnPtr& rowIdColumn : context->rowIdColumns)
-    {
-        for (QString& alias : rowIdColumn->queryExecutorAliasToColumn.keys())
-        {
-            if (!first)
-                outerColumns += sepTokens;
-
-            outerColumns << TokenPtr::create(Token::OTHER, alias);
-            first = false;
-        }
-    }
-
-    //QString t = outerColumns.detokenize(); // keeping it for debug purposes
-    select->tokens = wrapSelect(select->tokens, outerColumns);
-}
-
 bool QueryExecutorColumns::isRowIdColumn(const QString& columnAlias)
 {
     // In case of "SELECT * FROM (SELECT * FROM test);" the SelectResolver will return ROWID columns twice for each table listed,

SQLiteStudio3/coreSQLiteStudio/db/queryexecutorsteps/queryexecutorcolumns.h

@@ -66,7 +66,6 @@ class QueryExecutorColumns : public QueryExecutorStep
          */
         bool isRowIdColumnAlias(const QString& alias);
 
-        void wrapWithAliasedColumns(SqliteSelect* select);
         bool isRowIdColumn(const QString& columnAlias);
         QStringList rowIdColNames;
 };

SQLiteStudio3/coreSQLiteStudio/db/queryexecutorsteps/queryexecutorexecute.cpp

@@ -14,7 +14,7 @@
 
 bool QueryExecutorExecute::exec()
 {
-//    qDebug() << "q:" << context->processedQuery;
+    //qDebug() << "q:" << context->processedQuery;
 
     startTime = QDateTime::currentMSecsSinceEpoch();
     return executeQueries();

SQLiteStudio3/coreSQLiteStudio/selectresolver.cpp

@@ -725,7 +725,19 @@ QList<SelectResolver::Column> SelectResolver::resolveSingleSourceSubSelect(Sqlit
 
 QList<SelectResolver::Column> SelectResolver::resolveOtherSource(SqliteSelect::Core::JoinSourceOther *otherSrc)
 {
-    return resolveSingleSource(otherSrc->singleSource);
+    QList<SelectResolver::Column> joinedColumns = resolveSingleSource(otherSrc->singleSource);
+    if (!otherSrc->joinConstraint || otherSrc->joinConstraint->expr)
+        return joinedColumns;
+
+    // Skip right-hand (aka "other") source column if it matches any of names listed in USING clause.
+    QSet<QString> usingColumns;
+    for (QString& colName : otherSrc->joinConstraint->columnNames)
+        usingColumns << colName.toLower();
+
+    return filter<SelectResolver::Column>(joinedColumns, [usingColumns](const SelectResolver::Column& col)
+    {
+        return !usingColumns.contains((col.alias.isNull() ? col.column : col.alias).toLower());
+    });
 }
 
 QList<SelectResolver::Column> SelectResolver::resolveSubSelect(SqliteSelect *select)
@@ -761,9 +773,15 @@ QList<SelectResolver::Column> SelectResolver::resolveSubSelect(SqliteSelect *sel
     }
     else
     {
+        static_qstring(colTpl, "%1.%2 AS %3");
+        auto fn = [](const Column& c) {return colTpl.arg(c.table, c.column, c.alias);};
+        QStringList resolverColumns = map<Column, QString>(columnSourcesFromInternal, fn);
+        QStringList sqliteColumns = map<Column, QString>(columnSources, fn);
         qCritical() << "Number of columns resolved by internal SchemaResolver is different than resolved by SQLite API:"
                     << columnSourcesFromInternal.size() << "!=" << columnSources.size()
-                    << ", therefore table alias may be identified incorrectly (from resolver, but not by SQLite API)";
+                    << ", therefore table alias may be identified incorrectly (from resolver, but not by SQLite API)"
+                    << ". Columns were resolved from query:" << query << ". Colums resolved by SchemaResolver:"
+                    << resolverColumns.join(", ") << ", while columns from SQLite:" << sqliteColumns.join(", ");
     }
 
     if (compound)

SQLiteStudio3/coreSQLiteStudio/sqlitestudio.cpp

@@ -42,7 +42,7 @@
 
 DEFINE_SINGLETON(SQLiteStudio)
 
-static const int sqlitestudioVersion = 30411;
+static const int sqlitestudioVersion = 30412;
 
 SQLiteStudio::SQLiteStudio()
 {