列转行聚合的简单实现ORACLE WM_CONCAT LISTAGG函数
WM_CONCAT Built-in Function (Not Supported)
If you are not running 11g Release 2, but are running a version of the database where the WM_CONCAT function is present, then it is a zero effort solution as it performs the aggregation for you. It is actually an example of a user defined aggregate function described below, but Oracle
have done all the work for you.
LISTAGG Analystic Function in 11g Release 2
The LISTAGG analytic function was introduced in Oracle 11g Release 2, making it very easy to aggregate strings. The nice thing about this function is it also allows us to order the elements in the concatenated list. If you are using 11g Release 2 you should use this function for string aggregation.
CREATE TABLE "TESTAGG"
"A" VARCHAR2(20 BYTE),
"B" VARCHAR2(20 BYTE)
INSERT INTO "TESTAGG" (A, B) VALUES ('1', 'B1')
INSERT INTO "TESTAGG" (A, B) VALUES ('1', 'B2')
INSERT INTO "TESTAGG" (A, B) VALUES ('1', 'B3')
INSERT INTO "TESTAGG" (A, B) VALUES ('2', 'B4')
INSERT INTO "TESTAGG" (A, B) VALUES ('2', 'B5')
INSERT INTO "TESTAGG" (A, B) VALUES ('3', 'B6')
select * from testAgg
select a ,wm_concat (b) as policinams from testagg group by a order by a
select a ,LISTAGG(b,',' ) within group(order by a) as b from testagg group by
select grantee,wm_concat(granted_role) as grante_role from dba_role_prives group by grantee;
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