Related
I browsed SO but could not quite find the exact answer or maybe it was for a different language.
Let's say I have a table, where each row is a record of a trade:
trade_id customer trade_date
1 A 2013-05-01 00:00:00
2 B 2013-05-01 10:00:00
3 A 2013-05-02 00:00:00
4 A 2013-05-05 00:00:00
5 B 2013-05-06 12:00:00
I would like to have the average time between trades, in days or fraction of days, for each customer, and the number of days since last trade. So for instance for customer A, time between trades 1 and 3 is 1 day and between trades 3 and 4 is 3 days, for an average of 2. So the end table would look like something like this (assuming today it's the 2013-05-10):
customer avg_time_btw_trades time_since_last_trade
A 2.0 5.0
B 5.08 3.5
If a customer has only got 1 trade I guess NULL is fine as output.
Not even sure SQL is the best way to do this (I am working with SQL server), but any help is appreciated!
SELECT
customer,
DATEDIFF(second, MIN(trade_date), MAX(trade_date)) / (NULLIF(COUNT(*), 1) - 1) / 86400.0,
DATEDIFF(second, MAX(trade_date), GETDATE() ) / 86400.0
FROM
yourTable
GROUP BY
customer
http://sqlfiddle.com/#!6/eb46e/7
EDIT: Added final field that I didn't notice, apologies.
The following SQL script uses your data and gives the expected results.
DECLARE #temp TABLE
( trade_id INT,
customer CHAR(1),
trade_date DATETIME );
INSERT INTO #temp VALUES (1, 'A', '20130501');
INSERT INTO #temp VALUES (2, 'B', '20130501 10:00');
INSERT INTO #temp VALUES (3, 'A', '20130502');
INSERT INTO #temp VALUES (4, 'A', '20130505');
INSERT INTO #temp VALUES (5, 'B', '20130506 12:00');
DECLARE #getdate DATETIME
-- SET #getdate = getdate();
SET #getdate = '20130510';
SELECT s.customer
, AVG(s.days_btw_trades) AS avg_time_between_trades
, CAST(DATEDIFF(hour, MAX(s.trade_date), #getdate) AS float)
/ 24.0 AS time_since_last_trade
FROM (
SELECT CAST(DATEDIFF(HOUR, t2.trade_date, t.trade_date) AS float)
/ 24.0 AS days_btw_trades
, t.customer
, t.trade_date
FROM #temp t
LEFT JOIN #temp t2 ON t2.customer = t.customer
AND t2.trade_date = ( SELECT MAX(t3.trade_date)
FROM #temp t3
WHERE t3.customer = t.customer
AND t3.trade_date < t.trade_date)
) s
GROUP BY s.customer
You need a date difference between every trade and average them.
select
a.customer
,avg(datediff(a.trade_date, b.trade_date))
,datediff(now(),max(a.trade_date))
from yourTable a, yourTable b
where a.customer = b.customer
and b.trade_date = (
select max(trade_date)
from yourTable c
where c.customer = a.customer
and a.trade_date > c.trade_date)
#gets the one earlier date for every trade
group by a.customer
Just for grins I added a solution that would use CTE's. You could probably use a temp table if the first query is too large. I used #MatBailie creation script for the table:
CREATE TABLE customer_trades (
id INT IDENTITY(1,1),
customer_id INT,
trade_date DATETIME,
PRIMARY KEY (id),
INDEX ix_user_trades (customer_id, trade_date)
)
INSERT INTO
customer_trades (
customer_id,
trade_date
)
VALUES
(1, '2013-05-01 00:00:00'),
(2, '2013-05-01 10:00:00'),
(1, '2013-05-02 00:00:00'),
(1, '2013-05-05 00:00:00'),
(2, '2013-05-06 12:00:00')
;
;WITH CTE as(
select customer_id, trade_date, datediff(hour,trade_date,ISNULL(LEAD(trade_date,1) over (partition by customer_id order by trade_date),GETDATE())) Trade_diff
from customer_trades
)
, CTE2 as
(SELECT customer_id, trade_diff, LAST_VALUE(trade_diff) OVER(Partition by customer_id order by trade_date) Curr_Trade from CTE)
SELECT Customer_id, AVG(trade_diff) AV, Max(Curr_Trade) Curr_Trade
FROM CTE2
GROUP BY customer_id
I have a table with columns of product and sold date, and want to query the statistics of sold interval of each product group(max interval, min interval ...) , is there any good advice to make it, appreciate~
Prod SaleDate
-------------------
A 2013-02-05
D 2013-02-24
B 2013-03-01
A 2013-03-12
D 2013-03-22
A 2013-04-03
D 2013-04-08
. . .
Sold interval means days interval between two adjacent date.
Sold interval of A:
DATEDIFF(d, '2013-02-05', '2013-03-12')
DATEDIFF(d, '2013-03-12', '2013-04-03')
...
Sold interval of D:
DATEDIFF(d, '2013-02-24', '2013-03-22')
DATEDIFF(d, '2013-03-22', '2013-04-08')
and I want get the average, max and min value of sold interval.
Prod IntervalAvg IntervalMax IntervalMin
-----------------------------------------------------
A xxx xxx xxx
B xxx xxx xxx
C
. . .
Thanks Kahn's answer give me a hint. I re-implement my code for sql server 2000 by "left outer join".
DECLARE #DATA TABLE (Prod CHAR(1), SaleDate SMALLDATETIME)
INSERT INTO #DATA VALUES ('A','2013-02-05')
INSERT INTO #DATA VALUES ('D','2013-02-24')
INSERT INTO #DATA VALUES ('B','2013-03-01')
INSERT INTO #DATA VALUES ('A','2013-03-12')
INSERT INTO #DATA VALUES ('D','2013-03-22')
INSERT INTO #DATA VALUES ('A','2013-04-03')
INSERT INTO #DATA VALUES ('D','2013-04-08')
SELECT
t.Prod
, MAX(t.Interval) IntervalMax
, MIN(t.Interval) IntervalMin
, AVG(t.Interval) IntervalAvg
FROM
(
SELECT t1.*, DATEDIFF(dd, MAX(t2.SaleDate), t1.SaleDate) Interval
FROM #DATA t1
LEFT OUTER JOIN #DATA t2 ON t1.Prod = t2.Prod AND t1.SaleDate > t2.SaleDate
GROUP BY t1.Prod, t1.SaleDate
)t
GROUP BY t.Prod
ORDER BY t.Prod
Here's one way that should work:
-- Test data
DECLARE #DATA TABLE (Prod CHAR(1), SaleDate DATE)
INSERT INTO #DATA VALUES ('A','2013-02-05')
,('D','2013-02-24')
,('B','2013-03-01')
,('A','2013-03-12')
,('D','2013-03-22')
,('A','2013-04-03')
,('D','2013-04-08')
-- Actual query
;WITH CTE AS
(SELECT D.*, CA.NextSaleDate
, DATEDIFF(DD, SaleDate, NextSaleDate) DDiff
FROM #DATA D
OUTER APPLY (SELECT MIN(SaleDate) NextSaleDate FROM #DATA B WHERE B.Prod = D.Prod AND B.SaleDate > D.SaleDate) CA)
SELECT DISTINCT Prod, AvgInterval, MaxInterval, MinInterval
FROM CTE C
CROSS APPLY (SELECT AVG(DDiff) AvgInterval, MAX(DDiff) MaxInterval, MIN(DDiff) MinInterval FROM CTE B WHERE B.Prod = C.Prod) CA
The Problem
I have a PostgreSQL database on which I am trying to summarize the revenue of a cash register over time. The cash register can either have status ACTIVE or INACTIVE, but I only want to summarize the earnings created when it was ACTIVE for a given period of time.
I have two tables; one that marks the revenue and one that marks the cash register status:
CREATE TABLE counters
(
id bigserial NOT NULL,
"timestamp" timestamp with time zone,
total_revenue bigint,
id_of_machine character varying(50),
CONSTRAINT counters_pkey PRIMARY KEY (id)
)
CREATE TABLE machine_lifecycle_events
(
id bigserial NOT NULL,
event_type character varying(50),
"timestamp" timestamp with time zone,
id_of_affected_machine character varying(50),
CONSTRAINT machine_lifecycle_events_pkey PRIMARY KEY (id)
)
A counters entry is added every 1 minute and total_revenue only increases. A machine_lifecycle_events entry is added every time the status of the machine changes.
I have added an image illustrating the problem. It is the revenue during the blue periods which should be summarized.
What I have tried so far
I have created a query which can give me the total revenue in a given instant:
SELECT total_revenue
FROM counters
WHERE timestamp < '2014-03-05 11:00:00'
AND id_of_machine='1'
ORDER BY
timestamp desc
LIMIT 1
The questions
How do I calculate the revenue earned between two timestamps?
How do I determine the start and end timestamps of the blue periods when I have to compare the timestamps in machine_lifecycle_events with the input period?
Any ideas on how to attack this problem?
Update
Example data:
INSERT INTO counters VALUES
(1, '2014-03-01 00:00:00', 100, '1')
, (2, '2014-03-01 12:00:00', 200, '1')
, (3, '2014-03-02 00:00:00', 300, '1')
, (4, '2014-03-02 12:00:00', 400, '1')
, (5, '2014-03-03 00:00:00', 500, '1')
, (6, '2014-03-03 12:00:00', 600, '1')
, (7, '2014-03-04 00:00:00', 700, '1')
, (8, '2014-03-04 12:00:00', 800, '1')
, (9, '2014-03-05 00:00:00', 900, '1')
, (10, '2014-03-05 12:00:00', 1000, '1')
, (11, '2014-03-06 00:00:00', 1100, '1')
, (12, '2014-03-06 12:00:00', 1200, '1')
, (13, '2014-03-07 00:00:00', 1300, '1')
, (14, '2014-03-07 12:00:00', 1400, '1');
INSERT INTO machine_lifecycle_events VALUES
(1, 'ACTIVE', '2014-03-01 08:00:00', '1')
, (2, 'INACTIVE', '2014-03-03 00:00:00', '1')
, (3, 'ACTIVE', '2014-03-05 00:00:00', '1')
, (4, 'INACTIVE', '2014-03-06 12:00:00', '1');
SQL Fiddle with sample data.
Example query:
The revenue between '2014-03-02 08:00:00' and '2014-03-06 08:00:00' is 300. 100 for the first ACTIVE period, and 200 for the second ACTIVE period.
DB design
To make my work easier I sanitized your DB design before I tackled the questions:
CREATE TEMP TABLE counter (
id bigserial PRIMARY KEY
, ts timestamp NOT NULL
, total_revenue bigint NOT NULL
, machine_id int NOT NULL
);
CREATE TEMP TABLE machine_event (
id bigserial PRIMARY KEY
, ts timestamp NOT NULL
, machine_id int NOT NULL
, status_active bool NOT NULL
);
Test case in the fiddle.
Major points
Using ts instead of "timestamp". Never use basic type names as column names.
Simplified & unified the name machine_id and made it out to be integer as it should be, instead of varchar(50).
event_type varchar(50) should be an integer foreign key, too, or an enum. Or even just a boolean for only active / inactive. Simplified to status_active bool.
Simplified and sanitized INSERT statements as well.
Answers
Assumptions
total_revenue only increases (per question).
Borders of the outer time frame are included.
Every "next" row per machine in machine_event has the opposite status_active.
1. How do I calculate the revenue earned between two timestamps?
WITH span AS (
SELECT '2014-03-02 12:00'::timestamp AS s_from -- start of time range
, '2014-03-05 11:00'::timestamp AS s_to -- end of time range
)
SELECT machine_id, s.s_from, s.s_to
, max(total_revenue) - min(total_revenue) AS earned
FROM counter c
, span s
WHERE ts BETWEEN s_from AND s_to -- borders included!
AND machine_id = 1
GROUP BY 1,2,3;
2. How do I determine the start and end timestamps of the blue periods when I have to compare the timestamps in machine_event with the input period?
This query for all machines in the given time frame (span).
Add WHERE machine_id = 1 in the CTE cte to select a specific machine.
WITH span AS (
SELECT '2014-03-02 08:00'::timestamp AS s_from -- start of time range
, '2014-03-06 08:00'::timestamp AS s_to -- end of time range
)
, cte AS (
SELECT machine_id, ts, status_active, s_from
, lead(ts, 1, s_to) OVER w AS period_end
, first_value(ts) OVER w AS first_ts
FROM span s
JOIN machine_event e ON e.ts BETWEEN s.s_from AND s.s_to
WINDOW w AS (PARTITION BY machine_id ORDER BY ts)
)
SELECT machine_id, ts AS period_start, period_end -- start in time frame
FROM cte
WHERE status_active
UNION ALL -- active start before time frame
SELECT machine_id, s_from, ts
FROM cte
WHERE NOT status_active
AND ts = first_ts
AND ts <> s_from
UNION ALL -- active start before time frame, no end in time frame
SELECT machine_id, s_from, s_to
FROM (
SELECT DISTINCT ON (1)
e.machine_id, e.status_active, s.s_from, s.s_to
FROM span s
JOIN machine_event e ON e.ts < s.s_from -- only from before time range
LEFT JOIN cte c USING (machine_id)
WHERE c.machine_id IS NULL -- not in selected time range
ORDER BY e.machine_id, e.ts DESC -- only the latest entry
) sub
WHERE status_active -- only if active
ORDER BY 1, 2;
Result is the list of blue periods in your image.
SQL Fiddle demonstrating both.
Recent similar question:
Sum of time difference between rows
ok, I have an answer, but I had to assume that the id of the machine_lifecycle_events can be used to determine accessor and predecessor. So for my solution to work better you should have a link between the active and inactive events. There might be also other ways to solve it but those would add even more complexity.
first, to get the revenue for all active periods per machine you can do the following:
select c.id_of_machine, cycle_id, cycle_start, cycle_end, sum(total_revenue)
from counters c join (
select e1.id as cycle_id,
e1.timestamp as cycle_start,
e2.timestamp as cycle_end,
e1.id_of_affected_machine as cycle_machine_id
from machine_lifecycle_events e1 join machine_lifecycle_events e2
on e1.id + 1 = e2.id and -- this should be replaced with a specific column to find cycles which belong together
e1.id_of_affected_machine = e2.id_of_affected_machine
where e1.event_type = 'ACTIVE'
) cycle
on c.id_of_machine = cycle_machine_id and
cycle_start <= c.timestamp and c.timestamp <= cycle_end
group by c.id_of_machine, cycle_id, cycle_start, cycle_end
order by c.id_of_machine, cycle_id
you can further use this query and add more where conditions to get the revenue only within a time frame or for specific machines:
select sum(total_revenue)
from counters c join (
select e1.id as cycle_id,
e1.timestamp as cycle_start,
e2.timestamp as cycle_end,
e1.id_of_affected_machine as cycle_machine_id
from machine_lifecycle_events e1 join machine_lifecycle_events e2
on e1.id + 1 = e2.id and -- this should be replaced with a specific column to find cycles which belong together
e1.id_of_affected_machine = e2.id_of_affected_machine
where e1.event_type = 'ACTIVE'
) cycle
on c.id_of_machine = cycle_machine_id and
cycle_start <= c.timestamp and c.timestamp <= cycle_end
where '2014-03-02 08:00:00' <= c.timestamp and c.timestamp <= '2014-03-06 08:00:00'
and c.id_of_machine = '1'
As mentioned in the beginning, and in the comments, my way of finding connecting events isn't suitable for any more complex examples with multiple machines. The easiest way would be to have another column which would always point to the preceding event. Another way would be to have a function which would find those events but this solution couldn't make use of indices.
Use self-join and build intervals table with actual status of each interval.
with intervals as (
select e1.timestamp time1, e2.timestamp time2, e1.EVENT_TYPE as status
from machine_lifecycle_events e1
left join machine_lifecycle_events e2 on e2.id = e1.id + 1
) select * from counters c
join intervals i on (timestamp between i.time1 and i.time2 or i.time2 is null)
and i.status = 'ACTIVE';
I didn't use aggregation to show the result set, you can do this simply, I think. Also I missed machineId to simplify demonstration of this pattern.
We have a time management system where our employees or contractors (resources) enter the hours they have worked, and we derive a cost for it. I have a table with the historic costs:
CREATE TABLE ResourceTimeTypeCost (
ResourceCode VARCHAR(32),
TimeTypeCode VARCHAR(32),
EffectiveDate DATETIME,
CostRate DECIMAL(12,2)
)
So I have one date field which marks the effective date. If we have a record which is
('ResourceA', 'Normal', '2012-04-30', 40.00)
and I add a record which is
('ResourceA', 'Normal', '2012-05-04', 50.00)
So all hours entered between the 30th April and the 3rd of May will be at £40.00, all time after midnight on the 4th will be at £50.00. I understand this in principle but how do you write a query expressing this logic?
Assuming my time table looks like the below
CREATE TABLE TimeEntered (
ResourceCode VARCHAR(32),
TimeTypeCode VARCHAR(32),
ProjectCode VARCHAR(32),
ActivityCode VARCHAR(32),
TimeEnteredDate DATETIME,
HoursWorked DECIMAL(12,2)
)
If I insert the following records into the TimeEntered table
('ResourceA','Normal','Project1','Management1','2012-04-30',7.5)
('ResourceA','Normal','Project1','Management1','2012-05-01',7.5)
('ResourceA','Normal','Project1','Management1','2012-05-02',7.5)
('ResourceA','Normal','Project1','Management1','2012-05-03',7.5)
('ResourceA','Normal','Project1','Management1','2012-05-04',7.5)
('ResourceA','Normal','Project1','Management1','2012-05-07',7.5)
('ResourceA','Normal','Project1','Management1','2012-05-08',7.5)
I'd like to get a query that returns the total cost by resource
So in the case above it would be 'ResourceA', (4 * 7.5 * 40) + (3 * 7.5 * 50) = 2325.00
Can anyone provide a sample SQL query? I know this example doesn't make use of TimeType (i.e. it's always 'Normal') but I'd like to see how this is dealt with as well
I can't change the structure of the database. Many thanks in advance
IF OBJECT_ID ('tempdb..#ResourceTimeTypeCost') IS NOT NULL DROP TABLE #ResourceTimeTypeCost
CREATE TABLE #ResourceTimeTypeCost ( ResourceCode VARCHAR(32), TimeTypeCode VARCHAR(32), EffectiveDate DATETIME, CostRate DECIMAL(12,2) )
INSERT INTO #ResourceTimeTypeCost
SELECT 'ResourceA' as resourcecode, 'Normal' as timetypecode, '2012-04-30' as effectivedate, 40.00 as costrate
UNION ALL
SELECT 'ResourceA', 'Normal', '2012-05-04', 50.00
IF OBJECT_ID ('tempdb..#TimeEntered') IS NOT NULL DROP TABLE #TimeEntered
CREATE TABLE #TimeEntered ( ResourceCode VARCHAR(32), TimeTypeCode VARCHAR(32), ProjectCode VARCHAR(32), ActivityCode VARCHAR(32), TimeEnteredDate DATETIME, HoursWorked DECIMAL(12,2) )
INSERT INTO #TimeEntered
SELECT 'ResourceA','Normal','Project1','Management1','2012-04-30',7.5
UNION ALL SELECT 'ResourceA','Normal','Project1','Management1','2012-05-01',7.5
UNION ALL SELECT 'ResourceA','Normal','Project1','Management1','2012-05-02',7.5
UNION ALL SELECT 'ResourceA','Normal','Project1','Management1','2012-05-03',7.5
UNION ALL SELECT 'ResourceA','Normal','Project1','Management1','2012-05-04',7.5
UNION ALL SELECT 'ResourceA','Normal','Project1','Management1','2012-05-07',7.5
UNION ALL SELECT 'ResourceA','Normal','Project1','Management1','2012-05-08',7.5
;with ranges as
(
select
resourcecode
,TimeTypeCode
,EffectiveDate
,costrate
,row_number() OVER (PARTITION BY resourcecode,timetypecode ORDER BY effectivedate ASC) as row
from #ResourceTimeTypeCost
)
,ranges2 AS
(
SELECT
r1.resourcecode
,r1.TimeTypeCode
,r1.EffectiveDate
,r1.costrate
,r1.effectivedate as start_date
,ISNULL(DATEADD(ms,-3,r2.effectivedate),GETDATE()) as end_date
FROM ranges r1
LEFT OUTER JOIN ranges r2 on r2.row = r1.row + 1 --joins onto the next date row
AND r2.resourcecode = r1.resourcecode
AND r2.TimeTypeCode = r1.TimeTypeCode
)
SELECT
tee.resourcecode
,tee.timetypecode
,tee.projectcode
,tee.activitycode
,SUM(ranges2.costrate * tee.hoursworked) as total_cost
FROM #TimeEntered tee
INNER JOIN ranges2 ON tee.TimeEnteredDate >= ranges2.start_date
AND tee.TimeEnteredDate <= ranges2.end_date
AND tee.resourcecode = ranges2.resourcecode
AND tee.timetypecode = ranges2.TimeTypeCode
GROUP BY tee.resourcecode
,tee.timetypecode
,tee.projectcode
,tee.activitycode
What you have is a cost table that is, as some would say, a slowly changing dimension. First, it will help to have an effective and end date for the cost table. We can get this by doing a self join and group by:
with costs as
(select c.ResourceCode, c.EffectiveDate as effdate,
dateadd(day, -1, min(c1.EffectiveDate)) as endDate,
datediff(day, c.EffectiveDate, c1.EffectiveDate) - 1 as Span
from ResourceTimeTypeCost c left outer join
ResourceTimeTypeCost c1
group by c.ResourceCode, c.EffectiveDate
)
Although you say you cannot change the table structure, when you have a slowly changing dimension, having an effective and end date is good practice.
Now, you can use this infomation with TimeEntered as following:
select te.*, c.CostRate * te.HoursWorked as dayCost
from TimeEntered te join
Costs c
on te.ResouceCode = c.ResourceCode and
te.TimeEntered between c.EffDate and c.EndDate
To summarize by Resource for a given time range, the full query would look like:
with costs as
(select c.ResourceCode, c.EffectiveDate as effdate,
dateadd(day, -1, min(c1.EffectiveDate)) as endDate,
datediff(day, c.EffectiveDate, c1.EffectiveDate) - 1 as Span
from ResourceTimeTypeCost c left outer join
ResourceTimeTypeCost c1
group by c.ResourceCode, c.EffectiveDate
),
te as
(select te.*, c.CostRate * te.HoursWorked as dayCost
from TimeEntered te join
Costs c
on te.ResouceCode = c.ResourceCode and
te.TimeEntered between c.EffDate and c.EndDate
)
select te.ResourceCode, sum(dayCost)
from te
where te.TimeEntered >= <date1> and te.TimeEntered < <date2>
You might give this a try. CROSS APPLY will find first ResourceTimeTypeCost with older or equal date and same ResourceCode and TimeTypeCode as current record from TimeEntered.
SELECT te.ResourceCode,
te.TimeTypeCode,
te.ProjectCode,
te.ActivityCode,
te.TimeEnteredDate,
te.HoursWorked,
te.HoursWorked * rttc.CostRate Cost
FROM TimeEntered te
CROSS APPLY
(
-- First one only
SELECT top 1 CostRate
FROM ResourceTimeTypeCost
WHERE te.ResourceCode = ResourceTimeTypeCost.ResourceCode
AND te.TimeTypeCode = ResourceTimeTypeCost.TimeTypeCode
AND te.TimeEnteredDate >= ResourceTimeTypeCost.EffectiveDate
-- By most recent date
ORDER BY ResourceTimeTypeCost.EffectiveDate DESC
) rttc
Unfortunately I can no longer find article on msdn, hence the blog in link above.
Live test # Sql Fiddle.
SQL novice here. I'm trying to generate a costing query that outputs employee time card information and calculates cost based on an effective employee costing rate.
My question is similar to the one asked here: Retro-active effective date changes with overlapping dates but I'm not dealing with retro-activity or overlapping date ranges.
Table examples (null values in the rate table indicate current rate):
CREATE TABLE Emp_Rate
(
Emp int,
Rate money,
Rate_Start datetime,
Rate_Exp datetime
)
CREATE TABLE Emp_Time
(
Emp int,
Chrg_Date datetime,
Chrg_Code varchar(10),
Chrg_Hrs decimal(8, 2)
)
Insert into Emp_Rate (Emp,Rate,Rate_Start,Rate_Exp) Values ('1','20','5/1/09','4/30/10')
Insert into Emp_Rate (Emp,Rate,Rate_Start,Rate_Exp) Values ('1','21','5/1/10','4/30/11')
Insert into Emp_Rate (Emp,Rate,Rate_Start,Rate_Exp) Values ('1','22','5/1/11',NULL)
Insert into Emp_Time (Emp,Chrg_Date,Chrg_Code,Chrg_Hrs) Values ('1','5/10/09','B','8')
Insert into Emp_Time (Emp,Chrg_Date,Chrg_Code,Chrg_Hrs) Values ('1','5/10/10','B','8')
Insert into Emp_Time (Emp,Chrg_Date,Chrg_Code,Chrg_Hrs) Values ('1','5/10/11','B','8')
The query (returns dupes caused by multiple rate entries(obviously)):
Select Emp_Time.Emp,
Cast(Emp_Time.Chrg_Date as DATE) as 'Chrg_Date',
Emp_Time.Chrg_Code,
Emp_Time.Chrg_Hrs,
Emp_Rate.Rate,
Emp_Time.Chrg_Hrs * Emp_Rate.Rate as 'Cost'
From Emp_Time inner join
Emp_Rate on Emp_Rate.Emp = Emp_Time.Emp
Order By [Emp],[Chrg_Date]
Desired output:
Emp Chrg_Date Chrg_Code Chrg_Hrs Rate Cost
1 2009-05-10 B 8.00 20.00 160.00
1 2010-05-10 B 8.00 21.00 168.00
1 2011-05-10 B 8.00 22.00 176.00
I've gone around in circles using the Between operator in a sub query to isolate the correct rate based on the charge date, but have not had any luck.
I appreciate any help!
You didn't specify the DBMS type the answer below is for sql-server. I am sure there are other ways to do this but this way will replace the null Rate_Exp date with the current date.
Select et.Emp,
Cast(et.Chrg_Date as DATEtime) as 'Chrg_Date',
et.Chrg_Code,
et.Chrg_Hrs,
er.Rate,
et.Chrg_Hrs * er.Rate as 'Cost'
From Emp_Time et
inner join
(
SELECT Emp
, Rate
, Rate_Start
, CASE
WHEN Rate_Exp is Null
THEN Convert(varchar(10), getdate(), 101)
ELSE Rate_Exp
END as Rate_Exp
FROM Emp_Rate
)er
on er.Emp = et.Emp
WHERE (et.Chrg_Date BETWEEN er.Rate_Start AND er.Rate_Exp)
Order By et.Emp,et.Chrg_Date
OR use the CASE Statement in your WHERE Clause:
Select et.Emp,
Cast(et.Chrg_Date as DATEtime) as 'Chrg_Date',
et.Chrg_Code,
et.Chrg_Hrs,
er.Rate,
et.Chrg_Hrs * er.Rate as 'Cost'
From Emp_Time et
inner join Emp_Rate er
on er.Emp = et.Emp
WHERE (et.Chrg_Date
BETWEEN er.Rate_Start
AND CASE WHEN er.Rate_Exp Is Null
THEN Convert(varchar(10), getdate(), 101)
ELSE er.Rate_Exp END)