这个查询有什么问题？我正试图在红移上运行，但我得到了错误import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.Polygon;
import java.awt.image.BufferedImage;
import javafx.application.Application;
import javafx.embed.swing.SwingFXUtils;
import javafx.scene.Scene;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.image.WritableImage;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
/**
* @see https://stackoverflow.com/q/44136040/230513
*/
public class BufferedImageTest extends Application {
private static final int PANEL_WIDTH = 600, PANEL_HEIGHT = 600;
private static final int TRI_WIDTH = 500, TRI_HEIGHT = 500;
private static final int SIDE_GAP = (PANEL_WIDTH - TRI_WIDTH) / 2;
private static final int TOP_GAP = (PANEL_HEIGHT - TRI_HEIGHT) / 2;
private final int numberOfLevels = 13;
private int countTriangles;
@Override
public void start(Stage stage) {
stage.setTitle("BufferedImageTest");
StackPane root = new StackPane();
Scene scene = new Scene(root);
root.getChildren().add(new ImageView(createImage()));
stage.setScene(scene);
stage.show();
}
private Image createImage() {
BufferedImage bi = new BufferedImage(
PANEL_WIDTH, PANEL_HEIGHT, BufferedImage.TYPE_INT_ARGB);
Graphics2D g = bi.createGraphics();
g.setPaint(Color.white);
g.fillRect(0, 0, PANEL_WIDTH, PANEL_HEIGHT);
Point top = new Point(PANEL_WIDTH / 2, TOP_GAP);
Point left = new Point(SIDE_GAP, TOP_GAP + TRI_HEIGHT);
Point right = new Point(SIDE_GAP + TRI_WIDTH, TOP_GAP + TRI_HEIGHT);
g.setColor(Color.red);
long startTime = System.currentTimeMillis();
drawTriangle(g, numberOfLevels, top, left, right);
g.setPaint(Color.black);
g.drawString("Number of triangles: " + countTriangles, 15, 15);
g.drawString("Time : " + (System.currentTimeMillis() - startTime) + " ms", 15, 35);
g.drawString("Levels: " + numberOfLevels, 15, 50);
WritableImage image = SwingFXUtils.toFXImage(bi, null);
g.dispose();
return image;
}
private void drawTriangle(Graphics2D g, int levels, Point top, Point left, Point right) {
if (levels < 0) {
return;
}
countTriangles++;
Polygon tri = new Polygon();
tri.addPoint(top.x, top.y);
tri.addPoint(left.x, left.y);
tri.addPoint(right.x, right.y);
g.drawPolygon(tri);
// Get the midpoint on each edge in the triangle
Point p12 = midpoint(top, left);
Point p23 = midpoint(left, right);
Point p31 = midpoint(right, top);
// recurse on 3 triangular areas
drawTriangle(g, levels - 1, top, p12, p31);
drawTriangle(g, levels - 1, p12, left, p23);
drawTriangle(g, levels - 1, p31, p23, right);
}
private Point midpoint(Point p1, Point p2) {
return new Point((p1.x + p2.x) / 2, (p1.y + p2.y) / 2);
}
public static void main(String[] args) {
launch(args);
}
}
。
这两个表有文件名，我希望发现它们共享哪些文件以及它们没有（我需要知道在这种情况下哪个文件有文件）。 如果它们共享，则文件名将出现在两列上，如果它们不共享，则文件名将仅出现在具有它的表的列上，而另一列将为空/空。有些行具有相同的文件名，这就是我使用distinct的原因。我使用substring来忽略扩展名。
could not devise a query plan for the given query答案 0 :(得分：0)
您收到此错误是因为您不能在左连接字段上使用公式，因此您应该至少使用以下内容：
select *
from table1 a
FULL JOIN table2 r
ON a.filename_without_ext = SUBSTRING(r.filename,1,LEN(r.filename) - 4)
它会起作用的。
文件名不是唯一的事实不重要