群組函式

Oracle SQL 入門

Hadrien Lacroix

Content Developer

彙總資料

彙總資料

Oracle SQL 入門

群組函式

 

 

群組函式

  • SUM
  • AVG
  • MEDIAN
  • MIN
  • MAX
  • COUNT
Oracle SQL 入門

SUM

SELECT SUM(Milliseconds)
FROM Track
| SUM(Milliseconds) |
|-------------------|
| 1,378,778,040     |
Oracle SQL 入門

AVG、MEDIAN

SELECT AVG(Milliseconds), MEDIAN(Milliseconds)
FROM Track
| AVG(Milliseconds) | MEDIAN(Milliseconds) |
|-------------------|----------------------|
| 393,599.2         | 255,634              |
Oracle SQL 入門

MIN、MAX

SELECT MIN(Milliseconds), MAX(Milliseconds)
FROM Track
| MIN(Milliseconds) | MAX(Milliseconds) |
|-------------------|-------------------|
| 1,071             | 5,286,953         |
Oracle SQL 入門

COUNT

-- Number of rows in a table
SELECT COUNT(*)
FROM Track
-- Number of rows with non-null values
SELECT COUNT(Milliseconds)
FROM Track
-- Number of distinct non-null values
SELECT COUNT(DISTINCT Milliseconds)
FROM Track
| COUNT(*) |
|----------|
| 3503     |
| COUNT(Milliseconds) |
|---------------------|
| 3503                |
| COUNT(DISTINCT Milliseconds) |
|------------------------------|
| 3080                         |
Oracle SQL 入門

欄位別名

SELECT MIN(Milliseconds)
       SUM(Milliseconds)
FROM Track
| MIN(Milliseconds) | SUM(Milliseconds) |
|-------------------|-------------------|
| 1,071             | 1,378,778,040     |
SELECT MIN(Milliseconds) AS minimum
       SUM(Milliseconds) AS "Total Duration"
FROM Track
| MINIMUM           | Total Duration    |
|-------------------|-------------------|
| 1,071             | 1,378,778,040     |
Oracle SQL 入門

資料型別

數值資料 文字資料 日期資料
AVG x
SUM x
MIN x x x
MAX x x x
COUNT x x x
Oracle SQL 入門

文字(Character)

CHAR, VARCHAR2

SELECT Name 
FROM Track
| Name           |
|----------------|
| Ashes To Ashes |
| Layla          |
| Everlong       |
| ...            |
Oracle SQL 入門

數值(Numeric)

NUMBER

SELECT Milliseconds 
FROM Track
| Milliseconds |
|--------------|
| 343719       |
| 205688       |
| 267728       |
| ...          |
Oracle SQL 入門

日期(Date)

DATE, DATETIME

SELECT BirthDate 
FROM Employee
| BirthDate  |
|------------|
| 1962-02-18 |
| 1958-12-08 |
| 1973-08-29 |
| ...        |
Oracle SQL 入門

一起來練習吧!

Oracle SQL 入門

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