mysql - Read For Learn

How to export a mysql database using Command Prompt?

First check if your command line recognizes mysql command. If not go to command & type in: Then use this command to export your database: You will then be prompted for the database password. This exports the database to the path you are currently in, while executing this command Note: Here are some detailed instructions regarding both import … Read more

grabbing first row in a mysql query only

To return only one row use LIMIT 1: It doesn’t make sense to say ‘first row’ or ‘last row’ unless you have an ORDER BY clause. Assuming you add an ORDER BY clause then you can use LIMIT in the following ways: To get the first row use LIMIT 1. To get the 2nd row you can use limit with an … Read more

Commands out of sync; you can’t run this command now

You can’t have two simultaneous queries because mysqli uses unbuffered queries by default (for prepared statements; it’s the opposite for vanilla mysql_query). You can either fetch the first one into an array and loop through that, or tell mysqli to buffer the queries (using $stmt->store_result()). See here for details.

#1045 – Access denied for user ‘root’@’localhost’ (using password: YES)

The problem was I have 2 instances of Mysql installed and I didn’t know the password for both instances.Just check if port 80 is used by any of the programs. This is what I did 1.Quit Skype because it was using port 80.(Please check if port 80 is used by any other program). 2.Search for … Read more

Data truncated for column?

Your problem is that at the moment your incoming_Cid column defined as CHAR(1) when it should be CHAR(34). To fix this just issue this command to change your columns’ length from 1 to 34 Here is SQLFiddle demo

Getting connection failed: php_network_getaddresses: getaddrinfo failed: Name or service not known

Thanks Prerak, This is the answer, my database is on the same machine so I just needed to edit: Now everything is working just fine.

ERROR 1452: Cannot add or update a child row: a foreign key constraint fails

I have created tables in MySQL Workbench as shown below : ORDRE table: PRODUKT table: and ORDRELINJE table: so when I try to insert values into ORDRELINJE table i get: Error Code: 1452. Cannot add or update a child row: a foreign key constraint fails (srdjank.Ordrelinje, CONSTRAINT Ordrelinje_fk FOREIGN KEY (Ordre) REFERENCES Ordre (OrdreID)) I’ve … Read more

Fix Access denied for user ‘root’@’localhost’ for phpMyAdmin

Find config.inc file under C:\wamp\apps\phpmyadmin3.5.1 Inside this file find this one line and replace it with

Simple Random Samples from a Sql database

There’s a very interesting discussion of this type of issue here: http://www.titov.net/2005/09/21/do-not-use-order-by-rand-or-how-to-get-random-rows-from-table/ I think with absolutely no assumptions about the table that your O(n lg n) solution is the best. Though actually with a good optimizer or a slightly different technique the query you list may be a bit better, O(m*n) where m is the number … Read more

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