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best: SELECT * FROM ( SELECT A.*, ROWNUM RN FROM (SELECT * FROM tf_f_theme) A WHERE ROWNUM <= 40)WHERE RN >= 30 batter: select * from (select a.*,rownum rn from(select * from tf_f_theme) a) where RN BETWEEN 21 AND 40 update tablename colname=replace( colname, string_to_replace, [ replacement_string ] ) In Oracle/PLSQL, the replace function replaces a sequence of characters in a string with another set of characters. The syntax for the replace function is: replace( string1, string_to_replace, [ replacement_string ] ) string1 is the string to replace a sequence of characters with another set of characters. string_to_replace is the string that will be searched for in string1. replacement_string is optional. All occurrences of string_to_replace will be replaced with replacement_string in string1. If the replacement_string parameter is omitted, the replace function simply removes all occurrences of string_to_replace, and returns the resulting string. For example: replace('123123tech', '123'); would return 'tech' replace('123tech123', '123'); would return 'tech' replace('222tech', '2', '3'); would return '333tech' replace('0000123', '0'); would return '123' replace('0000123', '0', ' '); would return ' 123' public Connection get Connection() { try{ String strUrl=CONNECTION_STRING+"?user="+username+"&password="+password+"&useUnicode=true&characterEncoding=gb2312"; conn=DriverManager.getConnection(strUrl);} catch(Exception e) {con=null;} } return con; } 1,mysql 利用MySQL的一个特性实现MySQL查询结果的分页显示 来源:本文出自: 作者: (2001-07-05 18:08:00) 在mysql中利用select语句的一个特性就可以很方便地实现查询结果的分页，select语句的语法： SELECT [STRAIGHT_JOIN] [SQL_SMALL_RESULT] [SQL_BIG_RESULT] [HIGH_PRIORITY] [DISTINCT | DISTINCTROW | ALL] select_expression,... [INTO OUTFILE 'file_name' export_options] [FROM table_references [WHERE where_definition] [GROUP BY col_name,...] [HAVING where_definition] [ORDER BY {unsigned_integer | col_name | formula} [ASC | DESC] ,...] [LIMIT [offset,] rows] [PROCEDURE procedure_name] ] LIMIT子句可以用来限制由SELECT语句返回过来的数据数量，它有一个或两个参数，如果给出两个参数， 第一个参数指定返回的第一行在所有数据中的位置，从0开始（注意不是1），第二个参数指定最多返回行 数。例如： select * from table LIMIT 5,10; #返回第6-15行数据 select * from table LIMIT 5; #返回前5行 select * from table LIMIT 0,5; #返回前5行 (http://www.fanqiang.com)