diff --git a/pglab/CodeEditor.cpp b/pglab/CodeEditor.cpp
index 6c8c44d..64a1df8 100644
--- a/pglab/CodeEditor.cpp
+++ b/pglab/CodeEditor.cpp
@@ -17,6 +17,7 @@ CodeEditor::CodeEditor(QWidget *parent)
 	connect(this, SIGNAL(blockCountChanged(int)), this, SLOT(updateGutterAreaWidth(int)));
 	connect(this, SIGNAL(updateRequest(QRect,int)), this, SLOT(updateGutterArea(QRect,int)));
 	connect(this, SIGNAL(cursorPositionChanged()), this, SLOT(highlightCurrentLine()));
+	connect(this, SIGNAL(textChanged()), this, SLOT(onTextChanged()));
 
 	updateGutterAreaWidth(0);
 	highlightCurrentLine();
@@ -31,7 +32,7 @@ int CodeEditor::gutterAreaWidth()
 		++digits;
 	}
 
-	int space = 3 + fontMetrics().width(QLatin1Char('9')) * digits;
+	int space = 3 + fontMetrics().width(QLatin1Char('9')) * (digits + 2);
 
 	return space;
 }
@@ -61,20 +62,55 @@ void CodeEditor::resizeEvent(QResizeEvent *e)
 }
 
 void CodeEditor::highlightCurrentLine()
+{
+	QTextEdit::ExtraSelection selection;
+	QColor lineColor = QColor(Qt::yellow).lighter(160);
+	selection.format.setBackground(lineColor);
+	selection.format.setProperty(QTextFormat::FullWidthSelection, true);
+	selection.cursor = textCursor();
+	selection.cursor.clearSelection();
+	currentLine = selection;
+
+	updateExtraSelections();
+}
+
+void CodeEditor::onTextChanged()
+{
+	clearErrorMarkers();
+}
+
+void CodeEditor::addErrorMarker(int position, int length)
+{
+	QTextEdit::ExtraSelection selection;
+	QColor lineColor = QColor(Qt::red).lighter(160);
+	selection.format.setBackground(lineColor);
+	selection.format.setFontItalic(true);
+	selection.cursor = textCursor();
+	selection.cursor.setPosition(position);
+	int lineno = selection.cursor.blockNumber();
+	errorLines.insert(lineno);
+	selection.cursor.movePosition(QTextCursor::Right, QTextCursor::KeepAnchor, length);
+	errorMarkers.append(selection);
+
+	update();
+
+	updateExtraSelections();
+}
+
+void CodeEditor::clearErrorMarkers()
+{
+	errorMarkers.clear();
+	errorLines.clear();
+	update();
+	updateExtraSelections();
+}
+
+void CodeEditor::updateExtraSelections()
 {
 	QList<QTextEdit::ExtraSelection> extraSelections;
-
-	if (!isReadOnly()) {
-		QTextEdit::ExtraSelection selection;
-
-		QColor lineColor = QColor(Qt::yellow).lighter(160);
-
-		selection.format.setBackground(lineColor);
-		selection.format.setProperty(QTextFormat::FullWidthSelection, true);
-		selection.cursor = textCursor();
-		selection.cursor.clearSelection();
-		extraSelections.append(selection);
-	}
+	extraSelections.append(currentLine);
+	for (auto e : errorMarkers)
+		extraSelections.append(e);
 
 	setExtraSelections(extraSelections);
 }
@@ -102,6 +138,12 @@ void CodeEditor::gutterAreaPaintEvent(QPaintEvent *event)
 			painter.setPen(Qt::black);
 			painter.drawText(0, top, gutterArea->width(), fontMetrics().height(),
 							 Qt::AlignRight, number);
+
+			if (errorLines.count(blockNumber) > 0) {
+				int s = fontMetrics().height() - 8;
+				painter.setBrush(QBrush(Qt::red));
+				painter.drawEllipse(4, top + 4, s, s);
+			}
 		}
 
 		block = block.next();
diff --git a/pglab/CodeEditor.h b/pglab/CodeEditor.h
index f2a86d4..62b97bb 100644
--- a/pglab/CodeEditor.h
+++ b/pglab/CodeEditor.h
@@ -2,6 +2,7 @@
 #define CODEEDITOR_H
 
 #include <QPlainTextEdit>
+#include <set>
 
 class CodeEditor : public QPlainTextEdit
 {
@@ -12,6 +13,8 @@ public:
 	void gutterAreaPaintEvent(QPaintEvent *event);
 	int gutterAreaWidth();
 
+	void addErrorMarker(int position, int length);
+	void clearErrorMarkers();
 protected:
 	void resizeEvent(QResizeEvent *event) override;
 
@@ -23,9 +26,17 @@ private slots:
 	void updateGutterAreaWidth(int newBlockCount);
 	void highlightCurrentLine();
 	void updateGutterArea(const QRect &, int);
+	void onTextChanged();
 
 private:
 	QWidget *gutterArea;
+
+	QTextEdit::ExtraSelection currentLine;
+	QList<QTextEdit::ExtraSelection> errorMarkers;
+
+	std::set<int> errorLines;
+
+	void updateExtraSelections();
 };
 
 #endif // CODEEDITOR_H
diff --git a/pglab/QueryTab.cpp b/pglab/QueryTab.cpp
index 1e1c378..f489b79 100644
--- a/pglab/QueryTab.cpp
+++ b/pglab/QueryTab.cpp
@@ -512,7 +512,9 @@ void QueryTab::query_ready(Expected<std::shared_ptr<Pgsql::Result>> exp_res, qin
     //					statusBar()->showMessage(tr("No tuples returned, possibly an error..."));
     //				}
                     ui->tabWidget->setCurrentWidget(ui->messageTab);
-                    receiveNotice(dbres->diagDetails());
+					auto details = dbres->diagDetails();
+					markError(details);
+					receiveNotice(details);
                 }
             }
         }
@@ -526,6 +528,37 @@ void QueryTab::query_ready(Expected<std::shared_ptr<Pgsql::Result>> exp_res, qin
     }
 }
 
+void QueryTab::markError(const Pgsql::ErrorDetails &details)
+{
+
+	if (details.statementPosition > 0) {
+		QTextCursor cursor = ui->queryEdit->textCursor();
+		cursor.setPosition(details.statementPosition-1);
+		ui->queryEdit->setTextCursor(cursor);
+
+		int length = 0;
+		if (details.state == "42703") {
+			int pos = details.messagePrimary.find('"');
+			if (pos != std::string::npos) {
+				int pos2 = details.messagePrimary.find('"', pos+1);
+				if (pos2 != std::string::npos) {
+					length = pos2 - pos;
+				}
+			}
+		}
+		else if (details.state == "42P01") {
+			int pos = details.messagePrimary.find('"');
+			if (pos != std::string::npos) {
+				int pos2 = details.messagePrimary.find('"', pos+1);
+				if (pos2 != std::string::npos) {
+					length = pos2 - pos;
+				}
+			}
+		}
+		ui->queryEdit->addErrorMarker(details.statementPosition-1, length);
+	}
+}
+
 void QueryTab::clearResult()
 {
 	for (auto e : resultList)
diff --git a/pglab/QueryTab.h b/pglab/QueryTab.h
index 89bf7ff..5c3350e 100644
--- a/pglab/QueryTab.h
+++ b/pglab/QueryTab.h
@@ -15,6 +15,10 @@ namespace Ui {
 	class QueryTab;
 }
 
+namespace Pgsql {
+	class ErrorDetails ;
+}
+
 class QTableView;
 
 class QTabWidget;
@@ -95,6 +99,7 @@ private:
 	QTabWidget *getTabWidget();
 	void setTabCaption(const QString &caption, const QString &tooltip);
 	void clearResult();
+	void markError(const Pgsql::ErrorDetails &details);
 
 private slots: