在 gram.y 中:
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simple_select:
SELECT opt_distinct target_list
into_clause from_clause where_clause
group_clause having_clause window_clause
{
SelectStmt *n = makeNode(SelectStmt);
n->distinctClause = $2;
n->targetList = $3;
n->intoClause = $4;
n->fromClause = $5;
n->whereClause = $6;
n->groupClause = $7;
n->havingClause = $8;
n->windowClause = $9;
$$ = (Node *)n;
}
……
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把它修改一下，增加：
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simple_select:
SELECT opt_distinct target_list
into_clause from_clause where_clause
group_clause having_clause window_clause
{
SelectStmt *n = makeNode(SelectStmt);
n->distinctClause = $2;
n->targetList = $3;
n->intoClause = $4;
n->fromClause = $5;
n->whereClause = $6;
n->groupClause = $7;
n->havingClause = $8;
n->windowClause = $9;
$$ = (Node *)n;
fprintf(stderr,"length of list: %d\n", n->targetList->length);
}
……
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psql 中执行： select id, name from a8;
后台出现： length of list: 2
本文转自健哥的数据花园博客园博客，原文链接：http://www.cnblogs.com/gaojian/archive/2012/09/06/2673589.html，如需转载请自行联系原作者
