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撰写电脑技术杂文十余年

sql***SELECT***语句实例

ebook | 2007-10-7 13:18:52 | 被阅次数 | 6402

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***SELECT***

  select *(列名) from table_name(表名) where column_name operator
  value
  ex:(宿主)
  select * from stock_information where stockid = str(nid)
  stockname = 'str_name'
  stockname like '% find this %'
  stockname like '[a-zA-Z]%' --------- ([]指定值的范围)
  stockname like '[^F-M]%' --------- (^排除指定范围)
  --------- 只能在使用like关键字的where子句中使用通配符)
  or stockpath = 'stock_path'
  or stocknumber < 1000
  and stockindex = 24
  not stock*** = 'man'
  stocknumber between 20 and 100
  stocknumber in(10,20,30)
  order by stockid desc(asc) --------- 排序,desc-降序,asc-升序
  order by 1,2 --------- by列号
  stockname = (select stockname from stock_information where
  stockid = 4)
  --------- 子查询
  --------- 除非能确保内层select只返回一个行的值,
  --------- 否则应在外层where子句中用一个in限定符
  select distinct column_name form table_name ---------
  distinct指定检索独有的列值,不重复
  select stocknumber ,"stocknumber + 10" = stocknumber + 10 from
  table_name
  select stockname , "stocknumber" = count(*) from table_name
  group by stockname
  --------- group by 将表按行分组,指定列中有相同的值
  having count(*) = 2 --------- having选定指定的组

  select *
  from table1, table2
  where table1.id *= table2.id --------
  左外部连接,table1中有的而table2中没有得以null表示
  table1.id =* table2.id -------- 右外部连接

  select stockname from table


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