MySQL update if value is greater than current value

While working with MySQL database there might be situation when you wish to update certain column only if the value being updated is greater than existing value or current value stored in that column. MySQL GREATEST and LEAST functions are quite handy in such situations. Let’s see how can we use first function to update a column if value is greater than current value.

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Facebook app is still in development mode & don’t have access

When you setup App on Facebook and try to make login with Facebook available in your script, everything seems fine but when someone attempt to login with a Facebook account he/she gets either of these errors from Facebook: App Not Setup: This app is still in development mode, and you don’t have access to it. Switch to a registered test user or ask an app admin for permissions. The developers of this app have not set up this app properly for Facebook Login.

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Placing text above foreground image in html

It’s quite common to use background image and place text above it but it’s also possible to use image in foreground and place text above foreground image overlay. You can also horizontal center or vertical center the text as explained in the article.

So our page contains a piece of HTML as follow:

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2 ways to center a column in Twitter Bootstrap 3

Here are 2 ways which you can use whenever you need to center a column div within `.container` in Twitter Bootstrap 3 as well as to keep empty space outside the `div` to be evenly distributed. First approach uses offset feature available in Bootstrap while it has a limitation and second approach is using `center-block` class with setting `float: none` in Twitter Bootstrap.

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Make the Footer Stick to the Bottom of a Page

When a page contains a large amount of content, the footer is pushed down off the viewport, and if you scroll down, the page ‘ends’ at the footer. However, If the page has small amount of content, the footer can sometimes ‘cling’ to the bottom of the content, floating halfway down the page, and leaving a blank space underneath, which looks ugly. So we need to make the footer stick to the bottom of page (not always fixed and visible).

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How to set scroll position to bottom in a div using javascript

Generally we create a div with the content and dynamically update the content. Further, we want to maintain the scroll position according to updated content. So there is one question of how to set scroll position to bottom in a div using JavaScript. Same type of problem I faced few days ago when I was working with a ajax message application and I am trying to get a div to scroll to the bottom when chat is updated.

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2 ways to truncate foreign key constrained table

In MySQL we create tables and build relationship among them. In the process if we need to truncate foreign key constrained table then we can’t do it simply and MySQL will throw an error even we have already removed table having foreign key constraint:

ERROR 1701 (42000): Cannot truncate a table referenced in a foreign key constraint…

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