SELECT
ID AS "线索编号" ,
CLEW_NAME AS "线索标题",
EVENT_CATEGORY AS "涉事类别",
MAIN AS "涉事主体",
(
SELECT WMSYS.WM_CONCAT(CLEW_ID)
FROM T_ZDSJ_CLEW_INFO aa
WHERE aa.RELEVANCE_ID = a.CLEW_ID
) AS "关联线索",
(
SELECT COUNT(*)
FROM T_ZDSJ_CLEW_INFO aa
WHERE aa.RELEVANCE_ID = a.CLEW_ID
) AS "关联数"
FROM T_ZDSJ_CLEW_INFO a
WHERE 1=1
ORDER BY "关联数" DESC
一般是用在FROM子句后面，对表名的起的索引名称。
特别是要进行多条件复合性关联查询时，索引名可以起到提高取表名的效率，方便语句操作。
比如：
FROM T_ZDSJ_CLEW_INFO aa
WHERE aa.RELEVANCE_ID = a.CLEW_ID
T_ZDSJ_CLEW_INFO表-> aa
T_ZDSJ_CLEW_INFO表->a
where条件关联，就直接可以用索引名来替代。
特别是要进行多条件复合性关联查询时，索引名可以起到提高取表名的效率，方便语句操作。
比如：
FROM T_ZDSJ_CLEW_INFO aa
WHERE aa.RELEVANCE_ID = a.CLEW_ID
T_ZDSJ_CLEW_INFO表-> aa
T_ZDSJ_CLEW_INFO表->a
where条件关联，就直接可以用索引名来替代。
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