-- http://www.sqlserver-dba.com/2011/09/this-is-a-followup-on-my-earlier-post-of-sql-server-test-data-generation-testing-tools-i-had-some-requests-for-my-set-up-pr.html
SELECT O_YEAR, SUM(CASE WHEN NATION = 'BRAZIL' THEN VOLUME ELSE 0 END)/SUM(VOLUME) AS MKT_SHARE
FROM (SELECT datepart(yy,O_ORDERDATE) AS O_YEAR, L_EXTENDEDPRICE*(1-L_DISCOUNT) AS VOLUME, N2.N_NAME AS NATION
 FROM PART, SUPPLIER, LINEITEM, ORDERS, CUSTOMER, NATION N1, NATION N2, REGION
 WHERE P_PARTKEY = L_PARTKEY AND S_SUPPKEY = L_SUPPKEY AND L_ORDERKEY = O_ORDERKEY
 AND O_CUSTKEY = C_CUSTKEY AND C_NATIONKEY = N1.N_NATIONKEY AND
 N1.N_REGIONKEY = R_REGIONKEY AND R_NAME = 'AMERICA' AND S_NATIONKEY = N2.N_NATIONKEY
 AND O_ORDERDATE BETWEEN '1995-01-01' AND '1996-12-31' AND P_TYPE= 'ECONOMY ANODIZED STEEL') AS ALL_NATIONS
GROUP BY O_YEAR
ORDER BY O_YEAR