如何通过表达式在组中创建CLOB列？任何工作？

我有以下查询：如何通过表达式在组中创建CLOB列？任何工作？

SELECT 
    Test_Case_Name, 
    Test_Case_Description, 
    Test_Case_Status, 
CASE WHEN Test_Case_Status = 'FAILED' THEN 
    LISTAGG(LN.LN_BUG_ID,', ') WITHIN GROUP(ORDER BY LN.LN_BUG_ID) 
END AS Defect_ID 
FROM Test LEFT JOIN LINK LN ON 
    LN.LN_ENTITY_ID=Test.TS_TEST_ID 
GROUP BY 
    Test_Case_Name, 
    Test_Case_Description, 
    Test_Case_Status

当我运行此查询，我得到的错误

ORA-00932：预期不一致的数据类型有CLOB

这是因为列Test_Case_Description是一个CLOB数据类型。如果我从select子句中注释这个列，它可以正常工作，但我需要输出中的这一列。

以上查询是原始查询here

来源

2012-12-25 javanoob

这里的简化版本，你可能需要使用您的要求的语法：

语法：

DBMS_LOB.SUBSTR (lob_loc, amount, offset) 

Parameter Description 
lob_loc: Locator for the LOB to be read i.e CLOB column name. 
amount: Number of bytes (for BLOBs) or characters (for CLOBs) to be read. 
offset: Offset in bytes (for BLOBs) or characters (for CLOBs) from the start of the LOB (origin: 1).

因此，最终的查询应该是这样的，

SELECT 
    Test_Case_Name, 
    DBMS_LOB.SUBSTR(Test_Case_Description,2000,1) as Test_Case_Description, 
    Test_Case_Status, 
CASE WHEN Test_Case_Status = 'FAILED' THEN 
    LISTAGG(LN.LN_BUG_ID,', ') WITHIN GROUP(ORDER BY LN.LN_BUG_ID) 
END AS Defect_ID 
FROM Test LEFT JOIN LINK LN ON 
    LN.LN_ENTITY_ID=Test.TS_TEST_ID 
GROUP BY 
    Test_Case_Name, 
    Test_Case_Description, 
    Test_Case_Status

既然你担心以后4000个字符不丢失数据，我的建议是分列和下面显示它..

SELECT 
    Test_Case_Name, 
    DBMS_LOB.SUBSTR(Test_Case_Description,4000,1) as Test_Case_Description1, 
    DBMS_LOB.SUBSTR(Test_Case_Description,8000,4001) as Test_Case_Description2 
    Test_Case_Status, 
CASE WHEN Test_Case_Status = 'FAILED' THEN 
    LISTAGG(LN.LN_BUG_ID,', ') WITHIN GROUP(ORDER BY LN.LN_BUG_ID) 
END AS Defect_ID 
FROM Test LEFT JOIN LINK LN ON 
    LN.LN_ENTITY_ID=Test.TS_TEST_ID 
GROUP BY 
    Test_Case_Name, 
    Test_Case_Description1, 
    Test_Case_Description2, 
    Test_Case_Status

来源

2012-12-25 18:54:08 Mari

但是这只有4000个字符的限制吧？ – javanoob

是的，在这种情况下，你可以在plsql块中打印该列。 PL SQL块有超过4000个字符的限制。 – Mari

请你让我知道如何做到这一点？任何链接？非常感谢 – javanoob

我只是改变了我的查询如下提到的，它的工作：

SELECT 
    InnerTable.Test_Case_Name, 
    Test.Test_Case_Description, 
    InnerTable.Test_Case_Status, 
FROM 
    ( SELECT 
    Test_Case_ID 
    Test_Case_Name, 
    Test_Case_Status, 
CASE WHEN Test_Case_Status = 'FAILED' THEN 
    LISTAGG(LN.LN_BUG_ID,', ') WITHIN GROUP(ORDER BY LN.LN_BUG_ID) 
END AS Defect_ID 
FROM Test LEFT JOIN LINK LN ON 
    LN.LN_ENTITY_ID=Test.TS_TEST_ID 
GROUP BY 
    Test_Case_Name, 
    Test_Case_Status) AS InnerTable INNERJOIN TEST ON InnerTable.Test_Case_ID = Test.Test_Case_ID

来源

2012-12-26 22:25:49 javanoob

如何通过表达式在组中创建CLOB列？任何工作？

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