SQL 按年提取结果

Question

问题：我已经在表格中存储了工资信息的日期。我需要每年显示一个结果。对于每一年，我想显示前一年的最大日期记录。问题是有些年份没有数据（工资没有变化）。我需要这些行包含该年之前的最大记录（可能是 2 年前甚至 3 年前）。

如果每一行都有数据，我现在的查询就可以工作……但它不考虑没有数据的年份。如何更新此 sql 以获取以下所需结果：

数据示例：

sch_sal_svc.beg_date -------sch_sal_svc.beg_date.per_plan_data

• 1/1/2007---100
• 6/1/2007---200
• 1/1/2008---300
• 1/1/2011---400
• 8/1/2011---500
• 9/1/2012---600

当前结果

• 1/1/2008---200
• 1/1/2011---300
• 1/1/2012---500

期望的结果

• 1/1/2008---200
• 1/1/2009---300
• 1/1/2010---300
• 1/1/2011---300
• 1/1/2012---500

SQL：

SELECT
years.control_id,
years.ssn,
ebe.plan_id,
to_number(to_char(years.sal_date,'yyyy')),
null as per_plan_salary,
    null as per_vest_hours,
    null as per_credsvc_hours,
    LEAST(s.rate_1,cl.comp_genl),
    null as salary_1,
    null as per_comm,
    null as per_overtime,
    null as per_ncr,
    null as salary_2
FROM
    sch_sal_svc s
    , (select distinct ssn, control_id, TRUNC(beg_date,'YEAR') as sal_date from sch_sal_svc where beg_date > to_date('12/31/1900', 'mm/dd/yyyy')) years
    , employee_benefit_elig ebe, compliance_limits cl
WHERE
    years.ssn = ebe.ssn
    and years.control_id = ebe.control_id
    and to_number(to_char(years.sal_date,'yyyy')) = cl.limit_year
    and to_number(to_char(years.sal_date,'yyyy')) <= to_number(to_char(sysdate,'yyyy'))
    and s.beg_date = (
        select max(s2.beg_date) from sch_sal_svc s2
        where s2.ssn = years.ssn and s2.control_id = years.control_id
        and s2.beg_date <= years.sal_date
    )
    and s.ssn = years.ssn
    and s.control_id = years.control_id
    and ebe.benefit_id = 'DB'
    and ebe.control_id = 'CLIENT'
    and ebe.plan_id in ('100', '200')

Answer 1

CREATE TABLE sch_sal_svc
(
    beg_date      DATE
,   per_plan_data NUMBER
);


INSERT INTO sch_sal_svc VALUES(TO_DATE('01/01/2007', 'DD/MM/YYYY'), 100);
INSERT INTO sch_sal_svc VALUES(TO_DATE('06/01/2007', 'DD/MM/YYYY'), 200);
INSERT INTO sch_sal_svc VALUES(TO_DATE('01/01/2008', 'DD/MM/YYYY'), 300);
INSERT INTO sch_sal_svc VALUES(TO_DATE('01/01/2011', 'DD/MM/YYYY'), 400);
INSERT INTO sch_sal_svc VALUES(TO_DATE('08/01/2011', 'DD/MM/YYYY'), 500);
INSERT INTO sch_sal_svc VALUES(TO_DATE('09/01/2012', 'DD/MM/YYYY'), 600);


SELECT  MIN(beg_date) FROM sch_sal_svc;
-- 2007-01-01 00:00:00


SELECT  d.r_level + NUMTOYMINTERVAL(1, 'YEAR') AS d_date
,       NVL    -- the salary must be updated at least once in three years
        (
            NVL
            (
                NVL
                (
                    s.per_plan_data
                ,   LAG(s.per_plan_data, 1) OVER (PARTITION BY 1 ORDER BY d.r_level)
                )
            ,   LAG(s.per_plan_data, 2) OVER (PARTITION BY 1 ORDER BY d.r_level)
            )
        ,   LAG(s.per_plan_data, 3) OVER (PARTITION BY 1 ORDER BY d.r_level)
        ) AS lag_per_plan_data
FROM
(
        SELECT  DATE'2006-01-01' + NUMTOYMINTERVAL(LEVEL, 'YEAR') AS r_level    -- min beg_date minus 1
        FROM    DUAL
        CONNECT BY
                LEVEL < (SELECT TO_CHAR(MAX(beg_date), 'YYYY') - TO_CHAR(MIN(beg_date), 'YYYY') + 2 FROM sch_sal_svc)
)  d
LEFT    JOIN
(
        SELECT  beg_date
        ,       per_plan_data
        FROM    sch_sal_svc
        WHERE   (beg_date) IN
                (
                    SELECT  MAX(beg_date)
                    FROM    sch_sal_svc
                    GROUP   BY
                            TRUNC(beg_date, 'YYYY')
                )
)  s
ON      d.r_level = TRUNC(s.beg_date, 'YYYY')
;

/*
2008-01-01 00:00:00 200
2009-01-01 00:00:00 300
2010-01-01 00:00:00 300
2011-01-01 00:00:00 300
2012-01-01 00:00:00 500
2013-01-01 00:00:00 600
*/