sort操作中表名列名合并
隐藏string中的长度传参
sort测试
Merge remote-tracking branch 'zl0530/master'

Conflicts:
	LogicalQueryPlan/Sort.cpp
	Test/TestMain.cpp
2014.6.3 support sql:
SELECT L_RETURNFLAG,L_LINESTATUS,
SUM(L_QUANTITY),SUM(L_EXTENDEDPRICE),SUM(L_EXTENDEDPRICE*(1-L_DISCOUNT)),SUM(L_EXTENDEDPRICE*(1-L_DISCOUNT)*(1+L_TEX)),
count(*) FROM LINEITEM GROUP BY L_RETURNFLAG,L_LINESTATUS ORDER BY
L_RETURNFLAG,L_LINESTATUS;