Oracle 10g：聚合

Question

得到了下表：

表T

DATE_A    | DATE_B    | ERRCODE 
----------+-----------+--------
01/MAY/13 | 01/JUN/15 | X
01/DEC/17 | 01/FEB/18 | Y

表U

ERRCODE | ERRDESC
--------+-------------------------------------------
X       | Conflicting from : {1} and to Period : {2}
Y       | Periods : {1} and {2} overlap

如下代碼：

select period, wm_concat(errcode) as issues
from ((select DATE_A as period, errcode from T where DATE_A is not null) union all
      (select DATE_B, errcode from T where DATE_B is not null)
     ) di
group by period
order by period;

將Table T轉換如下：

PERIOD    | ISSUES
----------+--------
01/MAY/13 | X
01/JUN/15 | X
01/DEC/17 | Y
01/FEB/18 | Y

我想轉換上面的代碼，以便：

• 它將表T中的ERRDESC為表U的相應ERRDESC
• 將ERRDESC中的{1}和{2}分別DATE_A為DATE_A和DATE_B
• 將結果插入Table V

所以我嘗試了這個：

INSERT INTO v (
    period,
    issues
)
    SELECT
        period,
        wm_concat(issue) AS issues
    FROM
        (
            SELECT
                t.date_a AS period,
                replace( (
                    SELECT
                        u.errdesc AS issue
                    FROM
                        u
                    WHERE
                        t.errcode = u.errcode
                ),'{1}', t.date_a) AS issue
            FROM
                t
            WHERE
                t.date_a IS NOT NULL
            UNION ALL
            SELECT
                t.date_b,
                replace( (
                    SELECT
                        u.errdesc AS issue
                    FROM
                        u
                    WHERE
                        t.errcode = u.errcode
                ),'{2}', t.date_b)
            FROM
                t
            WHERE
                t.date_b IS NOT NULL
        ) di
    GROUP BY
        period;

但是我得到這個（ Table V ）：

PERIOD    | ISSUES
----------+--------
01/MAY/13 | Conflicting from : 01/MAY/13 and to Period : {2}
01/JUN/15 | Conflicting from : {1} and to Period : 01/JUN/15
01/DEC/17 | Periods : 01/DEC/17 and {2} overlap
01/FEB/18 | Periods : {1} and 01/FEB/18 overlap

我要尋找的不是結果（ Table V ）：

PERIOD    | ISSUES
----------+--------
01/MAY/13 | Conflicting from : 01/MAY/13 and to Period : 01/JUN/15
01/JUN/15 | Conflicting from : 01/MAY/13 and to Period : 01/JUN/15
01/DEC/17 | Periods : 01/DEC/17 and 01/FEB/18 overlap
01/FEB/18 | Periods : 01/DEC/17 and 01/FEB/18 overlap

原因是聯合之前的選擇都不知道date_b和之后的選擇都不知道date_a 。

題

如何修改最新代碼以獲得預期結果？

注意

CREATE TABLE T
   (     
    "DATE_A" DATE, 
    "DATE_B" DATE, 
    "ERRCODE" VARCHAR2(2)
   )  ;

Insert into T (DATE_A,DATE_B,ERRCODE) values (to_date('01/MAY/13','DD/MON/RR'),to_date('01/JUN/15','DD/MON/RR'),'X');
Insert into T (DATE_A,DATE_B,ERRCODE) values (to_date('01/DEC/17','DD/MON/RR'),to_date('01/FEB/18','DD/MON/RR'),'Y');

CREATE TABLE U
   (     
    "ERRCODE"  VARCHAR2(2), 
    "ERRDESC"  VARCHAR2(100)
   )  ;

Insert into U (ERRCODE, ERRDESC) values ('X','Conflicting from : {1} and to Period : {2}');
Insert into U (ERRCODE, ERRDESC) values ('Y','Periods : {1} and {2} overlap');

CREATE TABLE V
   (     
    "PERIOD"  DATE, 
    "ISSUES"  VARCHAR2(100)
   )  ;

commit;

Answer 1

我要做的方法是先將兩個表連接起來，然后在錯誤描述列中填充值，然后將其分成兩行，如下所示：

INSERT INTO v (period, issues)
WITH t AS (SELECT to_date('01/05/2013', 'dd/mm/yyyy') date_a, to_date('01/06/2015', 'dd/mm/yyyy') date_b, 'X' errcode FROM dual UNION ALL
           SELECT to_date('01/12/2017', 'dd/mm/yyyy') date_a, to_date('01/02/2018', 'dd/mm/yyyy') date_b, 'Y' errcode FROM dual),
     u AS (SELECT 'X' errcode, 'Conflicting from : {1} and to Period : {2}' errdesc FROM dual UNION ALL
           SELECT 'Y' errcode, 'Periods : {1} and {2} overlap' errdesc FROM dual),
 dummy AS (SELECT LEVEL rn FROM dual CONNECT BY LEVEL <= 2),
   res AS (SELECT t.date_a,
                  t.date_b,
                  REPLACE(REPLACE(u.errdesc, '{1}', to_char(t.date_a, 'dd/MON/yyyy', 'nls_date_language = english')), '{2}', to_char(t.date_b, 'dd/MON/yyyy', 'nls_date_language = english')) errdesc
           FROM   t
                  INNER JOIN u ON t.errcode = u.errcode)
SELECT CASE WHEN d.rn = 1 THEN res.date_a
            WHEN d.rn = 2 THEN res.date_b
       END period,
       errdesc
FROM   res
       CROSS JOIN dummy d
ORDER BY res.date_a, d.rn;

PERIOD      ERRDESC
----------- --------------------------------------------------------------------------------
01/05/2013  Conflicting from : 01/MAY/2013 and to Period : 01/JUN/2015
01/06/2015  Conflicting from : 01/MAY/2013 and to Period : 01/JUN/2015
01/12/2017  Periods : 01/DEC/2017 and 01/FEB/2018 overlap
01/02/2018  Periods : 01/DEC/2017 and 01/FEB/2018 overlap

這是一種堅定的態度。 如果您使用的是11g或更高版本，則可以利用UNPIVOT命令將行分成兩部分。 它通過創建一個虛擬子查詢來工作，該子查詢包含要為每個輸入行輸出的所需行數-在您的情況下為2。

然后，我們可以將其交叉連接到主要結果集，這意味着這些行是重復的。 然后，只需確定要在每行上顯示哪些列，瞧！

關於日期的幾點注意事項：

• 請始終將日期明確轉換為字符串，而不要依賴nls_date_format設置； 您在會話中可能擁有的東西可能與其他人完全不同。
• 年有四個數字。 請不要使用兩位數來強迫Oracle猜測，尤其是當您預先了解信息時！ 有時可能會因為使用“ RR”格式掩碼而得到意外結果。

Answer 2

通過簡單的解決方案（如下）可以工作：

INSERT INTO v (
    period,
    issues
)
    SELECT
        period,
        wm_concat(issue) AS issues
    FROM
        (
            SELECT
                date_a AS period,
                replace(replace( (
                    SELECT 
                        u.errdesc AS issue
                    FROM
                        u
                    WHERE
                        t.errcode = u.errcode
                ),'{1}',t.date_a),'{2}',t.date_b) AS issue
            FROM
                t
            WHERE
                date_a IS NOT NULL
            UNION ALL
            SELECT
                date_b,
                replace(replace( (
                    SELECT 
                        u.errdesc AS issue
                    FROM
                        u
                    WHERE
                        t.errcode = u.errcode
                ),'{1}',t.date_a),'{2}',t.date_b)
            FROM
                t
            WHERE
                date_b IS NOT NULL
        ) di
    GROUP BY
        period;

編輯：

但是，Boneist的解決方案更好。