Hvordan laver man CLOB kolonne i gruppe efter udtryk? Noget arbejde omkring?

Her er den syntaks, du måske vil bruge til dit krav:

Syntaks:

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). 

Så din endelige forespørgsel burde være sådan her,

    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

Da du er bekymret for ikke at miste data efter 4000 tegn, er mit forslag at opdele kolonnen og vise den som nedenfor.

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