Question

我需要使用表中其他列的值创建一些包含一些自动生成数据的列

我知道如果我做这样的事情就行了

CREATE TABLE #Temp(ColumnA VARCHAR(50), ColumnB INT)

INSERT INTO #Temp 
VALUES('NAME1', 1)
, ('NAME2', 1)
, ('NAME3', 1)
, ('NAME4', 2)
, ('NAME5', 2)
, ('NAME6', 3)
, ('NAME7', 3)

;WITH Numbered 
AS
(
SELECT ColumnA, ColumnB, ROW_NUMBER() OVER (PARTITION BY ColumnB ORDER BY ColumnA) AS RowNum
FROM #Temp 
)
,RecordCounts
AS
(
SELECT ColumnB, COUNT(1) AS RecordCount
FROM #Temp
GROUP BY ColumnB
)
,RecursiveCTE
AS
(
SELECT ColumnB, CONVERT(VARCHAR(50), ColumnA) AS ColumnA, RowNum
FROM Numbered 
WHERE RowNum = 1
UNION ALL
SELECT N.ColumnB, CONVERT(VARCHAR(50), R.ColumnA + ', ' + N.ColumnA), N.RowNum
FROM RecursiveCTE R 
    INNER JOIN Numbered N ON R.ColumnB = N.ColumnB 
        AND N.RowNum = R.RowNum + 1
)
SELECT ColumnA 
FROM RecursiveCTE R
INNER JOIN RecordCounts RC ON R.ColumnB = RC.ColumnB
    AND R.RowNum = RC.RecordCount 
ORDER BY R.ColumnB

DROP TABLE #Temp

但是，我想在添加查询中进行强制转换，但这不起作用

ALTER TABLE Directions ADD RevisedLat INT
UPDATE Directions SET RevisedLat = CAST(Latitude*3200/90 AS INT)

让这项工作最好的方法是什么？只是添加和更新？

Answer 1

尝试计算列

ALTER TABLE Directions 
ADD RevisedLat  as (Cast(Latitude*3200/90  as INT))

使用Cast in SQL创建列

1 个答案: