我有一个需要执行的SQL查询,它主要是在名为item_code的列中查找2个值。值是"FWDBAL“和"INVLATECHARGE",我需要它来计算上面两列的item_price之和。invoice_items where invoiceid='9' AND item_code='CADB-FWDBAL' AND item_code='CADB-INVLA
create查询中显示了索引使用的示例:create table test_index();select * from test_index where a =10select name from test_index where a=10 也许问题是select * from test_index where a =10select