Difference between revisions of "Running Total"

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Line 21: Line 21:
 
  FROM transact x JOIN transact y ON (x.whn>=y.whn)
 
  FROM transact x JOIN transact y ON (x.whn>=y.whn)
 
  GROUP BY x.whn, x.description, x.amount
 
  GROUP BY x.whn, x.description, x.amount
<p>If you want the money IN and money OUT to be separate a CASE expression can be used.</p>
+
<p>If you want the money IN and money OUT to be separate a <code>CASE</code> expression can be used.</p>
 
</div>
 
</div>
 
<source lang='sql' class='def'>SELECT w AS dte, d AS description,  
 
<source lang='sql' class='def'>SELECT w AS dte, d AS description,  

Revision as of 14:39, 30 July 2012

Keep a running total

schema:scott
DROP TABLE transact
 CREATE TABLE transact(
  whn DATE,
  description VARCHAR(20),
  amount INTEGER );
INSERT INTO transact VALUES ((2006,11,01),'Wages',50);
INSERT INTO transact VALUES ((2006,11,02),'Company Store',-10);
INSERT INTO transact VALUES ((2006,11,03),'Company Store',-10);
INSERT INTO transact VALUES ((2006,11,04),'Company Store',-10);
INSERT INTO transact VALUES ((2006,11,05),'Company Store',-10);
INSERT INTO transact VALUES ((2006,11,06),'Company Store',-10);

To calculate a running total a table needs to be joined to itself, each version can be called table x and table y.

SELECT x.whn, x.description, x.amount, 
SUM(y.amount) AS balance
FROM transact x JOIN transact y ON (x.whn>=y.whn)
GROUP BY x.whn, x.description, x.amount

If you want the money IN and money OUT to be separate a CASE expression can be used.

SELECT w AS dte, d AS description, 
CASE WHEN (a>=0) THEN a ELSE NULL END AS moneyIN,
CASE WHEN (a<0) THEN a ELSE NULL END AS moneyOUT,
balance FROM
(SELECT x.whn AS w, x.description AS d, 
 x.amount AS a, SUM(y.amount) AS balance
FROM transact x JOIN transact y ON (x.whn>=y.whn)
GROUP BY x.whn, x.description, x.amount) t
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