在 gram.y 中:
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; $$ = (Node *)n; } ……
把它修改一下,增加:
simple_select: SELECT opt_distinct target_list into_clause from_clause where_clause group_clause having_clause window_clause { SelectStmt *n = makeNode(SelectStmt); n->distinctClause = $2; n->targetList = $3; n->intoClause = $4; n->fromClause = $5; n->whereClause = $6; n->groupClause = $7; n->havingClause = $8; n->windowClause = $9; $$ = (Node *)n; fprintf(stderr,"length of list: %d\n", n->targetList->length); } ……
psql 中执行: select id, name from a8;
后台出现: length of list: 2