Question

试图了解SQL中GROUP BY的用法

我已经多次遇到此错误，并且我无法确定核心以在以后的时间解决

SELECT d.department_name
FROM departments d
JOIN employees e
ON (d.department_id = e.department_id)
GROUP BY d.department_name
HAVING (SELECT COUNT(*) FROM employees) > 5
AND e.commission_pct IS NOT NULL;

ORA-00979: not a GROUP BY expression
00979. 00000 -  "not a GROUP BY expression"
*Cause:    
*Action:
Error at Line: 7 Column: 5

Answer 1

应具有按组分组的列，这是其构建方式。因此，让您可以汇总或操纵分组依据的列。分组错误的原因是您使用了子查询，而不是分组依据或聚合的列。

简而言之，拥有与在何处相似，但是拥有拥有使您可以过滤组中的记录，这与用于过滤整个表本身的记录的地方不同

    SELECT d.department_name
   FROM departments d
    JOIN employees e
    ON (d.department_id = 
      e.department_id)
     Where
      e.commission_pct IS NOT NULL
   GROUP BY d.department_name
    HAVING  COUNT(*) > 5
   ;

Answer 2

您的语法错误，条件应该在where子句中，并且不应重新选择值

public class JavaFxOriginText extends Application  {

    public static void main(String[] args) {
        Application.launch(args);
    }

    @Override
    public void start(Stage primaryStage) throws Exception {
        Group root = new Group();
        Scene scene = new Scene(root, 100, 50, Color.WHITE);
        primaryStage.setScene(scene);
        primaryStage.show();

        for(int i=0; i<5; i++) {
            Text text = new Text(0, i*10, "Hello World! " + i);
            text.setFill(Color.BLACK);
            root.getChildren().add(text);
        }
    }
}

请参见more examples

在Oracle 11g上执行ORA-00979的原因是什么

2 个答案: