Select all columns except one in My. SQL? Select * is a SQL antipattern. It should not be used in production code for many reasons including: It takes a tiny bit longer to process. When things are run millions of times, those tiny bits can matter. A slow database where the slowness is caused by this type of sloppy coding throughout is the hardest kind to performance tune. It means you are probably sending more data than you need which causes both server and network bottlenecks. If you have an inner join, the chances of sending more data than you need are 1. It causes maintenance problems especially when you have added new columns that you do not want seen everywhere. Further if you have a new column, you may need to do something to the interface to determine what to do with that column. It can break views (I know this is true in SQl server, it may or may not be true in mysql). If someone is silly enough to rebuild the tables with the columns in a differnt order (which you shouldn't do but it happens all teh time), all sorts of code can break. Espcially code for an insert for example where suddenly you are putting the city into the address_3 field becasue without specifying, the database can only go on the order of the columns. This is bad enough when the data types change but worse when the swapped columns have the same datatype becasue you can go for sometime inserting bad data that is a mess to clean up. You need to care about data integrity. If it is used in an insert, it will break the insert if a new column is added in one table but not the other. It might break triggers. Trigger problems can be difficult to diagnose. Add up all this against the time it take to add in the column names (heck you may even have an interface that allows you to drag over the columns names (I know I do in SQL Server, I'd bet there is some way to do this is some tool you use to write mysql queries.) Let's see, "I can cause maintenance problems, I can cause performance problems and I can cause data integrity problems, but hey I saved five minutes of dev time." Really just put in the specific columns you want. I also suggest you read this book. SQL- Antipatterns- Programming- Pragmatic- Programmers- ebook/dp/B0. ![]() I'm trying to use a select statement to get all of the columns from a certain MySQL table except one. Is there a simple way to do this? EDIT: There are 53 columns in. Summary: in this tutorial, you will learn how to use MySQL cursor in stored procedures to iterate through a result set returned by a SELECT statement. ![]() A3. 76. BB2/ref=sr_1_1? UTF8& qid=1. 38. MySQL Select Query - Learn MySQL from basic to advanced covering database programming clauses command functions administration queries and usage along with PHP in. SQL injection - Wikipedia. A classification of SQL injection attacking vector as of 2. SQL injection is a code injection technique, used to attack data- driven applications, in which nefarious SQL statements are inserted into an entry field for execution (e. SQL injection must exploit a security vulnerability in an application's software, for example, when user input is either incorrectly filtered for string literalescape characters embedded in SQL statements or user input is not strongly typed and unexpectedly executed. SQL injection is mostly known as an attack vector for websites but can be used to attack any type of SQL database. SQL injection attacks allow attackers to spoof identity, tamper with existing data, cause repudiation issues such as voiding transactions or changing balances, allow the complete disclosure of all data on the system, destroy the data or make it otherwise unavailable, and become administrators of the database server. In a 2. 01. 2 study, it was observed that the average web application received 4 attack campaigns per month, and retailers received twice as many attacks as other industries.[2]History[edit]The first public discussions of SQL injection started appearing around 1. Phrack Magazine.[4]SQL injection (SQLI) was considered one of the top 1. Open Web Application Security Project.[5] In 2. SQLI was rated the number one attack on the OWASP top ten.[6] There are four main sub- classes of SQL injection: The Storm Worm is one representation of Compounded SQLI.[1. This classification represents the state of SQLI, respecting its evolution until 2. Technical implementations[edit]Incorrectly filtered escape characters[edit]This form of SQL injection occurs when user input is not filtered for escape characters and is then passed into an SQL statement. This results in the potential manipulation of the statements performed on the database by the end- user of the application. The following line of code illustrates this vulnerability. SELECT*FROMusers. WHEREname='" + user. Name + "'; ". This SQL code is designed to pull up the records of the specified username from its table of users. However, if the "user. Name" variable is crafted in a specific way by a malicious user, the SQL statement may do more than the code author intended. For example, setting the "user. Name" variable as. SQL comments[1. 3]). All three lines have a space at the end. OR '1'='1' - -. ' OR '1'='1' ({. OR '1'='1' /*. renders one of the following SQL statements by the parent language: SELECT*FROMusers. WHEREname=''OR'1'='1'; SELECT*FROMusers. WHEREname=''OR'1'='1'- - '; If this code were to be used in an authentication procedure then this example could be used to force the selection of every data field (*) from all users rather than from one specific user name as the coder intended, because the evaluation of '1'='1' is always true (short- circuit evaluation). The following value of "user. Name" in the statement below would cause the deletion of the "users" table as well as the selection of all data from the "userinfo" table (in essence revealing the information of every user), using an API that allows multiple statements. DROPTABLEusers; SELECT*FROMuserinfo. WHERE't'='t. This input renders the final SQL statement as follows and specified: SELECT*FROMusers. WHEREname='a'; DROPTABLEusers; SELECT*FROMuserinfo. WHERE't'='t'; While most SQL server implementations allow multiple statements to be executed with one call in this way, some SQL APIs such as PHP's mysql_query() function do not allow this for security reasons. This prevents attackers from injecting entirely separate queries, but doesn't stop them from modifying queries. Incorrect type handling[edit]This form of SQL injection occurs when a user- supplied field is not strongly typed or is not checked for type constraints. This could take place when a numeric field is to be used in a SQL statement, but the programmer makes no checks to validate that the user supplied input is numeric. For example. statement : = "SELECT*FROMuserinfo. WHEREid=" + a_variable + "; ". It is clear from this statement that the author intended a_variable to be a number correlating to the "id" field. However, if it is in fact a string then the end- user may manipulate the statement as they choose, thereby bypassing the need for escape characters. For example, setting a_variable to. DROP TABLE users. SQL becomes: SELECT*FROMuserinfo. WHEREid=1; DROPTABLEusers; Blind SQL injection[edit]Blind SQL Injection is used when a web application is vulnerable to an SQL injection but the results of the injection are not visible to the attacker. The page with the vulnerability may not be one that displays data but will display differently depending on the results of a logical statement injected into the legitimate SQL statement called for that page. This type of attack has traditionally been considered time- intensive because a new statement needed to be crafted for each bit recovered, and depending on its structure, the attack may consist of many unsuccessful requests. Recent advancements have allowed each request to recover multiple bits, with no unsuccessful requests, allowing for more consistent and efficient extraction. There are several tools that can automate these attacks once the location of the vulnerability and the target information has been established.[1. Conditional responses[edit]One type of blind SQL injection forces the database to evaluate a logical statement on an ordinary application screen. As an example, a book review website uses a query string to determine which book review to display. So the URLhttp: //books. Review. php? ID=5 would cause the server to run the query. SELECT*FROMbookreviews. WHEREID='Value(ID)'; from which it would populate the review page with data from the review with ID 5, stored in the table bookreviews. The query happens completely on the server; the user does not know the names of the database, table, or fields, nor does the user know the query string. The user only sees that the above URL returns a book review. A hacker can load the URLs http: //books. Review. php? ID=5. OR1=1 and http: //books. Review. php? ID=5. AND1=2, which may result in queries. SELECT*FROMbookreviews. WHEREID='5'OR'1'='1'; SELECT*FROMbookreviews. WHEREID='5'AND'1'='2'; respectively. If the original review loads with the "1=1" URL and a blank or error page is returned from the "1=2" URL, and the returned page has not been created to alert the user the input is invalid, or in other words, has been caught by an input test script, the site is likely vulnerable to a SQL injection attack as the query will likely have passed through successfully in both cases. The hacker may proceed with this query string designed to reveal the version number of My. SQL running on the server: http: //books. Review. php? ID=5. ANDsubstring(@@version,1,INSTR(@@version,'.')- 1)=4, which would show the book review on a server running My. SQL 4 and a blank or error page otherwise. The hacker can continue to use code within query strings to glean more information from the server until another avenue of attack is discovered or his or her goals are achieved.[1. Second order SQL injection[edit]Second order SQL injection occurs when submitted values contain malicious commands that are stored rather than executed immediately. In some cases, the application may correctly encode an SQL statement and store it as valid SQL. Then, another part of that application without controls to protect against SQL injection might execute that stored SQL statement. This attack requires more knowledge of how submitted values are later used. Automated web application security scanners would not easily detect this type of SQL injection and may need to be manually instructed where to check for evidence that it is being attempted. Mitigation[edit]An SQL injection is a well known attack and easily prevented by simple measures. After an apparent SQL injection attack on Talktalk in 2. BBC reported that security experts were stunned that such a large company would be vulnerable to it.[1. Parameterized statements[edit]With most development platforms, parameterized statements that work with parameters can be used (sometimes called placeholders or bind variables) instead of embedding user input in the statement. A placeholder can only store a value of the given type and not an arbitrary SQL fragment. Hence the SQL injection would simply be treated as a strange (and probably invalid) parameter value.
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