oracle和mysql的行列轉換

CREATE TABLE t(
class1 VARCHAR2(2 BYTE),
calldate DATE,
callcount INTEGER
);

INSERT INTO t(class1, calldate, callcount)
VALUES ('1', TO_DATE ('08/08/2005', 'MM/DD/YYYY'), 40);

INSERT INTO t(class1, calldate, callcount)
VALUES ('1', TO_DATE ('08/07/2005', 'MM/DD/YYYY'), 6);

INSERT INTO t(class1, calldate, callcount)
VALUES ('2', TO_DATE ('08/08/2005', 'MM/DD/YYYY'), 77);

INSERT INTO t(class1, calldate, callcount)
VALUES ('3', TO_DATE ('08/09/2005', 'MM/DD/YYYY'), 33);

INSERT INTO t(class1, calldate, callcount)
VALUES ('3', TO_DATE ('08/08/2005', 'MM/DD/YYYY'), 9);

INSERT INTO t(class1, calldate, callcount)
VALUES ('3', TO_DATE ('08/07/2005', 'MM/DD/YYYY'), 21);

COMMIT ;

oracle：

WMSYS.WM_CONCAT

SQL> select class1,wmsys.wm_concat(callcount) from t group by class1;

CLASS1 WMSYS.WM_CONCAT(CALLCOUNT)
------ --------------------------------------------------------------------------------
1 40,6
2 77
3 33,9,21

mysql :

group_concat

select class1,group_concat(callcount) from t group class1;

注意：group_concat(callcount)可能被截斷，因為有個引數規定了這個結果的長度，如果很長，需要修改這個引數！

ref：

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