語法錯誤：解析錯誤，創建迴歸測試時檢查空表

我正在創建一個迴歸測試查詢，該查詢將檢查表是否被填充。這是通過獲取每個表A，B，C中的第一行並且如果它的ID存在，它將得到值「Y」。如果不是，則值「N」。我創建了下面的代碼來執行以下操作，但是我得到了語法錯誤：解析錯誤。有人可以告訴我什麼是錯的嗎？語法錯誤：解析錯誤，創建迴歸測試時檢查空表

SELECT 

Case 
    When EXISTS(A.Id) THEN 'Y' 
    ELSE 'N' 
END AS A_exist, 

Case 
    When EXISTS(B.Id) THEN 'Y' 
    ELSE 'N' 
END AS B_exist, 

Case 
    When EXISTS(C.Id) THEN 'Y' 
    ELSE 'N' 
END AS C_exist 

FROM 
(select top 1 * from Table_A) A 
(select top 1 * from Table_B) B 
(select top 1 * from Table_C) C

來源

2015-05-29 Filip Eriksson

您可以強制使用空錶行中的COUNT：

SELECT 
    CASE WHEN a.CNT = 1 THEN 'Y' ELSE 'N' END AS A_exist, 
    CASE WHEN b.CNT = 1 THEN 'Y' ELSE 'N' END AS B_exist, 
    CASE WHEN c.CNT = 1 THEN 'Y' ELSE 'N' END AS C_exist 
FROM 
(
    SELECT COUNT(*) AS CNT 
    WHERE EXISTS(SELECT * FROM Table_A) 
) AS a, 
(
    SELECT COUNT(*) AS CNT 
    WHERE EXISTS(SELECT * FROM Table_B) 
) AS b, 
(
    SELECT COUNT(*) AS CNT 
    WHERE EXISTS(SELECT * FROM Table_C) 
) AS c;

但是你爲什麼不每個表返回一行而不是一列？延長要容易得多：

SELECT 'Table_A' AS "Table", CASE WHEN COUNT(*) = 1 THEN 'Y' ELSE 'N' END AS "Exists?" 
WHERE EXISTS(SELECT * FROM Table_A) 
UNION ALL 
SELECT 'Table_B', CASE WHEN COUNT(*) = 1 THEN 'Y' ELSE 'N' END 
WHERE EXISTS(SELECT * FROM Table_B) 
UNION ALL 
SELECT 'Table_C', CASE WHEN COUNT(*) = 1 THEN 'Y' ELSE 'N' END 
WHERE EXISTS(SELECT * FROM Table_C)

來源

2015-05-29 11:24:05 dnoeth

我給你第二個選擇，它完美的作品。謝謝！ –

你使用sql-server嗎？這是否工作？

SELECT 

Case 
    When EXISTS(select * from Table_A) THEN 'Y' 
    ELSE 'N' 
END AS A_exist, 

Case 
    When EXISTS(select * from Table_B) THEN 'Y' 
    ELSE 'N' 
END AS B_exist, 

Case 
    When EXISTS(select * from Table_C) THEN 'Y' 
    ELSE 'N' 
END AS C_exist

來源

2015-05-29 10:53:38

嗨。我收到了子查詢中不支持TOP N的反饋。我正在使用Teradata。 –

您可以使用下面的查詢。

SELECT 

Case 
    When A.Id IS NOT NULL THEN 'Y' 
    ELSE 'N' 
END AS A_exist, 

Case 
    When B.Id IS NOT NULL THEN 'Y' 
    ELSE 'N' 
END AS B_exist, 

Case 
    When C.Id IS NOT NULL THEN 'Y' 
    ELSE 'N' 
END AS C_exist 

FROM 
(select top 1 * from Table_A) A, 
(select top 1 * from Table_B) B, 
(select top 1 * from Table_C) C 
;

來源

2015-05-29 10:54:39

這個解決方案的問題是，如果一個表爲空，那麼我不會得到值'N'，而是整個reult集只是一個空表。我該如何解決這個問題？ –

在這種情況下，這個應該工作：SELECT 案例當A.Id IS NOT NULL THEN 'Y' ELSE 'N' END AS A_exist， 'N' AS B_EXIST， 'N' AS C_exist FROM （選擇頂部1 *從表-A）甲 UNION SELECT 'N' AS A_EXIST，案例當B.Id IS NOT NULL THEN 'Y' ELSE 'N' END AS B_exist， 'N' AS C_EXIST FROM （從表B中選擇頂部1 *）B UNION SELECT 'N' AS A_EXIST， 'N' AS B_EXIST，案例當C.ID THEN IS NOT NULL 'Y' ELSE 'N' END AS C_exist FROM （選擇頂部1 *從Table_C）C ; –

語法錯誤：解析錯誤，創建迴歸測試時檢查空表

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