Yes, something like this: As other answers have pointed out, MySQL also has the IF() function to do this using less verbose syntax. I generally try to avoid this because it is a MySQL-specific extension to SQL that isn’t generally supported elsewhere. CASE is standard SQL and is much more portable across different database engines, and I prefer to … Read more
Looks like the mysql server is not started. Look to the official documentation of MySQL how you can start a service under windows. Install the server as a service using this command: C:> “C:\Program Files\MySQL\MySQL Server 5.5\bin\mysqld” –install
An identifying relationship is when the existence of a row in a child table depends on a row in a parent table. This may be confusing because it’s common practice these days to create a pseudokey for a child table, but not make the foreign key to the parent part of the child’s primary key. Formally, the “right” way … Read more
I think the main reason is for data integrity. If you have a relationship between two tables invoice and invoice_item. You won’t be able to add an invoice item that does not related to an invoice. This is what you want! It’s called referential integrity. It can get pretty messy in your database if you don’t have … Read more
Basics SELECTing columns from a table Aggregates Part 1: COUNT, SUM, MAX/MIN Aggregates Part 2: DISTINCT, GROUP BY, HAVING Intermediate JOINs, ANSI-89 and ANSI-92 syntax UNION vs UNION ALL NULL handling: COALESCE & Native NULL handling Subqueries: IN, EXISTS, and inline views Subqueries: Correlated WITH syntax: Subquery Factoring/CTE Views Advanced Topics Functions, Stored Procedures, Packages Pivoting data: CASE & PIVOT syntax Hierarchical Queries Cursors: Implicit and Explicit Triggers Dynamic … Read more
So what is this “require?” require() is not part of the standard JavaScript API. But in Node.js, it’s a built-in function with a special purpose: to load modules. Modules are a way to split an application into separate files instead of having all of your application in one file. This concept is also present in other languages … Read more
It’s working as intended. Your MySQL server has been started with –secure-file-priv option which basically limits from which directories you can load files using LOAD DATA INFILE. You may use SHOW VARIABLES LIKE “secure_file_priv”; to see the directory that has been configured. You have two options: Move your file to the directory specified by secure-file-priv. … Read more
The problem is that you mapped your servlet to /register.html and it expects POST method, because you implemented only doPost() method. So when you open register.html page, it will not open html page with the form but servlet that handles the form data. Alternatively when you submit POST form to non-existing URL, web container will … Read more
Renaming a table is not working in MySQL The error message is The query is working fine on other tables for me, but not with the table group.
So what is this “require?” require() is not part of the standard JavaScript API. But in Node.js, it’s a built-in function with a special purpose: to load modules. Modules are a way to split an application into separate files instead of having all of your application in one file. This concept is also present in other languages … Read more