[FEATURE][expression] Add concatenate_unique() aggregation function

nirvn · nirvn · commit 578c3982193a · 2019-04-05T12:01:06.000+07:00
diff --git a/src/core/expression/qgsexpressionfunction.cpp b/src/core/expression/qgsexpressionfunction.cpp
@@ -888,6 +888,23 @@ static QVariant fcnAggregateStringConcat( const QVariantList &values, const QgsE
   return fcnAggregateGeneric( QgsAggregateCalculator::StringConcatenate, values, parameters, context, parent );
 }
 
+static QVariant fcnAggregateStringConcatUnique( const QVariantList &values, const QgsExpressionContext *context, QgsExpression *parent, const QgsExpressionNodeFunction * )
+{
+  QgsAggregateCalculator::AggregateParameters parameters;
+
+  //fourth node is concatenator
+  if ( values.count() > 3 )
+  {
+    QgsExpressionNode *node = QgsExpressionUtils::getNode( values.at( 3 ), parent );
+    ENSURE_NO_EVAL_ERROR;
+    QVariant value = node->eval( parent, context );
+    ENSURE_NO_EVAL_ERROR;
+    parameters.delimiter = value.toString();
+  }
+
+  return fcnAggregateGeneric( QgsAggregateCalculator::StringConcatenateUnique, values, parameters, context, parent );
+}
+
 static QVariant fcnAggregateArray( const QVariantList &values, const QgsExpressionContext *context, QgsExpression *parent, const QgsExpressionNodeFunction * )
 {
   return fcnAggregateGeneric( QgsAggregateCalculator::ArrayAggregate, values, QgsAggregateCalculator::AggregateParameters(), context, parent );
@@ -4909,6 +4926,7 @@ const QList<QgsExpressionFunction *> &QgsExpression::Functions()
         << new QgsStaticExpressionFunction( QStringLiteral( "max_length" ), aggParams, fcnAggregateMaxLength, QStringLiteral( "Aggregates" ), QString(), false, QSet<QString>(), true )
         << new QgsStaticExpressionFunction( QStringLiteral( "collect" ), aggParams, fcnAggregateCollectGeometry, QStringLiteral( "Aggregates" ), QString(), false, QSet<QString>(), true )
         << new QgsStaticExpressionFunction( QStringLiteral( "concatenate" ), aggParams << QgsExpressionFunction::Parameter( QStringLiteral( "concatenator" ), true ), fcnAggregateStringConcat, QStringLiteral( "Aggregates" ), QString(), false, QSet<QString>(), true )
+        << new QgsStaticExpressionFunction( QStringLiteral( "concatenate_unique" ), aggParams << QgsExpressionFunction::Parameter( QStringLiteral( "concatenator" ), true ), fcnAggregateStringConcatUnique, QStringLiteral( "Aggregates" ), QString(), false, QSet<QString>(), true )
         << new QgsStaticExpressionFunction( QStringLiteral( "array_agg" ), aggParams, fcnAggregateArray, QStringLiteral( "Aggregates" ), QString(), false, QSet<QString>(), true )
 
         << new QgsStaticExpressionFunction( QStringLiteral( "regexp_match" ), QgsExpressionFunction::ParameterList() << QgsExpressionFunction::Parameter( QStringLiteral( "string" ) ) << QgsExpressionFunction::Parameter( QStringLiteral( "regex" ) ), fcnRegexpMatch, QStringList() << QStringLiteral( "Conditionals" ) << QStringLiteral( "String" ) )
diff --git a/tests/src/core/testqgsexpression.cpp b/tests/src/core/testqgsexpression.cpp
@@ -1681,6 +1681,7 @@ class TestQgsExpression: public QObject
       QTest::newRow( "string aggregate 1" ) << "aggregate('test','min',\"col2\")" << false << QVariant( "test1" );
       QTest::newRow( "string aggregate 2" ) << "aggregate('test','min_length',\"col2\")" << false << QVariant( 5 );
       QTest::newRow( "string concatenate" ) << "aggregate('test','concatenate',\"col2\",concatenator:=' , ')" << false << QVariant( "test1 , test2 , test3 , test4" );
+      QTest::newRow( "string concatenate unique" ) << "aggregate('test','concatenate_unique',\"col2\",concatenator:=' , ')" << false << QVariant( "test1 , test2 , test3 , test4" );
 
       QTest::newRow( "geometry collect" ) << "geom_to_wkt(aggregate('aggregate_layer','collect',$geometry))" << false << QVariant( QStringLiteral( "MultiPoint ((0 0),(1 0),(2 0),(3 0),(5 0))" ) );
 
@@ -1769,6 +1770,7 @@ class TestQgsExpression: public QObject
       QTest::newRow( "min_length" ) << "min_length(\"col2\")" << false << QVariant( 0 );
       QTest::newRow( "max_length" ) << "max_length(\"col2\")" << false << QVariant( 7 );
       QTest::newRow( "concatenate" ) << "concatenate(\"col2\",concatenator:=',')" << false << QVariant( "test,,test333,test4,,test4" );
+      QTest::newRow( "concatenate unique" ) << "concatenate_unique(\"col4\",concatenator:=',')" << false << QVariant( ",test" );
 
       QTest::newRow( "geometry collect" ) << "geom_to_wkt(collect($geometry))" << false << QVariant( QStringLiteral( "MultiPoint ((0 0),(1 0),(2 0),(3 0),(5 0))" ) );
       QTest::newRow( "geometry collect with null geometry first" ) << "geom_to_wkt(collect($geometry, filter:=\"col3\"=3))" << false << QVariant( QStringLiteral( "MultiPoint ((5 0))" ) );
