Re: First and Last word in string Peter Brawley September 25, 2017 11:10AM Re: First and Last word in string Eder Pardeiro Eder Pardeiro September 25, 2017 11:39AM Sorry, you can't reply to this topic. It has been closed.
SELECTMID("RUNOOB",2,3)ASExtractString; -- UNO POSITION(s1 IN s)从字符串 s 中获取 s1 的开始位置 返回字符串 abc 中 b 的位置: SELECTPOSITION('b'in'abc')-- 2 REPEAT(s,n)将字符串 s 重复 n 次 将字符串 runoob 重复三次: SELECTREPEAT('runoob',3)-- runoobrunoobrunoob REPLACE(s,s1...
column_name为要更改的数据列 value为修改后的数据,可以为变量,具体值,表达式或者嵌套的SELECT结果 condition为筛选条件,如不指定则修改该表的所有列数据3.5 删除delete from命令语法:sql DELETE FROM 表名[WHERE condition];注意:condition为筛选条件 , 如不指定则删除该表的所有列数据...
ADD_SPATIAL_INDEX : Alter_inplace_infoadd_sql_mode_field() : dd::Object_table_definition_impladd_star() : dd::system_views::System_view_select_definition_impladd_star_select_item() : dd::info_schema::Select_lex_builderadd_state_listener() : metadata_cache::ClusterStateNotifierInterface, ...
SELECT IF(1 > 0, '正确', '错误'); SELECT IFNULL(null, 'Hello Word'); SELECT CASE WHEN 1 > 0 THEN '1 > 0' WHEN 2 > 0 THEN '2 > 0' ELSE '3 > 0' END; SELECT last_name, job_id, salary, CASE job_id WHEN 'a' THEN 1.1*salary WHEN 'b' THEN 1.2*salary...
having 用来操作 group by x 后 其他列按y分组后的每组信息 与in any all 结合使用 若比较改每小组中的集合与其他集合否相等 可转化为 相同条件下 数量之间的比较 select last_insert_id():函数,获取最后插入的id mybatis配置: 代码语言:javascript
mysqlinterprets instances of the delimiter string as a statement delimiter anywhere it occurs, except within quoted strings. Be careful about defining a delimiter that might occur within other words. For example, if you define the delimiter asX, it is not possible to use the wordINDEXin statemen...
SELECT ASCII(CustomerName) AS NumCodeOfFirstChar FROM Customers; CHAR_LENGTH(s) 返回字符串 s 的字符数 返回字符串 RUNOOB 的字符数 SELECT CHAR_LENGTH("RUNOOB") AS LengthOfString; CHARACTER_LENGTH(s) 返回字符串 s 的字符数,等同于 CHAR_LENGTH(s) 返回字符串 RUNOOB 的字符数 SELECT CHARACTER_LEN...
3.Select the code which shows the countries that end in A or L 4.Pick the result from the query SELECT name,length(name) FROM world WHERE length(name)=5 and continent='Europe' 5.Here are the first few rows of the world table: ...
select * from tablename where match(column1,column2) against ('+word1 +word2 -word3' in boolean mode') 布尔检索只能返回1或者0,不再返回表示匹配程度的浮点数 全文索引的缺陷: 数据表越大,全文索引效果好,比较小的数据表会返回一些难以理解的结果。