如何利用SQL查詢返回龐大的整數序列表

　　WITH Digits AS (
    SELECT 0 as Number
    UNION SELECT 1
    UNION SELECT 2
    UNION SELECT 3
    UNION SELECT 4
    UNION SELECT 5
    UNION SELECT 6
    UNION SELECT 7
    UNION SELECT 8
    UNION SELECT 9
)
SELECT
   (d5.Number * 100000)
    + (d4.Number * 10000)
    + (d3.Number * 1000)
    + (d2.Number * 100)
    + (d1.Number * 10)
    + d0.Number as Number
FROM
    Digits AS d0
    , Digits AS d1
    , Digits AS d2
    , Digits AS d3
    , Digits AS d4
    , Digits AS d5

在SQLServer 2005中,這個SQL返回一個包含1000000條記錄的結果集,從0到999999。
這條語句利用了SQL2005的新功能：CTE (Common Table Expression)
如果當前的數據庫是SQL 2000或其他不支持CTE的數據庫，則可以將WITH部分的SQL定義為一個視圖。

CREATE VIEW .[Digits] AS
SELECT 0 AS Number
UNION SELECT 1
UNION SELECT 2
UNION SELECT 3
UNION SELECT 4
UNION SELECT 5
UNION SELECT 6
UNION SELECT 7
UNION SELECT 8
UNION SELECT 9;

CREATE VIEW [MillionNumbers] AS
SELECT
SELECT (d5.Number * 100000)
    + (d4.Number * 10000)
    + (d3.Number * 1000)
    + (d2.Number * 100)
    + (d1.Number * 10)
    + d0.Number) as Number
FROM
    Digits AS d0
    , Digits AS d1
    , Digits AS d2
    , Digits AS d3
    , Digits AS d4
    , Digits AS d5;

　　我們可以用這個方法來生成大批量的測試數據。如：

INSERT INTO MyTest (RecordId, RecordIndex)
SELECT newid(), Number FROM MillionNumbers

　　用此方法插入數據，要比利用循環快很多倍。