jQuery Mobile 1.4.0

The jQuery Mobile team is excited to announce the first release candidate for 1.4.0. For this new version of the jQuery Mobile framework we focused on performance improvements, reviewing widgets as well as a new default theme and SVG icons. Some of the new features in 1.4 are a flip switch widget, a generic filter widget named “filterable”, popups with arrows, tooltips for sliders and we integrated the tabs widget from jQuery UI.
See the changelog below for the key changes, and have a look at the jQuery Mobile 1.4.0 Beta 1 announcement to find out about all highlights of this new version of jQuery Mobile.

Demos | Key changes | Download & CDN

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Difference between WHERE clause and HAVING clause

WHERE and HAVING both filters out records based on one or more conditions.

The difference is,

WHERE clause can only be applied on a static non-aggregated column whereas we will need to use HAVING for aggregated columns.

To understand this, consider this example. 

Suppose we want to see only those departments where department ID is greater than 3. There is no aggregation operation and the condition needs to be applied on a static field. We will use WHERE clause here:

SELECT * FROM DEPT WHERE ID > 3

Next, suppose we want to see only those Departments where Average salary is greater than 80. Here the condition is associated with a non-static aggregated information which is “average of salary”. We will need to use HAVING clause here:

SELECT dept.name DEPARTMENT, avg(emp.sal) AVG_SAL
FROM DEPT dept, EMPLOYEE emp
WHERE dept.id = emp.dept_id (+)
GROUP BY dept.name
HAVING AVG(emp.sal) > 80

What is the difference between inner and outer join?.

Inner Join

Inner join is the most common type of Join which is used to combine the rows from two tables and create a result set containing only such records that are present in both the tables based on the joining condition

SELECT dept.name DEPARTMENT, emp.name EMPLOYEE 
FROM DEPT dept, EMPLOYEE emp
WHERE emp.dept_id = dept.id

Outer Join

Outer Join, on the other hand, will return matching rows from both tables as well as any unmatched rows from one or both the tables (based on whether it is single outer or full outer join respectively).

Notice in our record set that there is no employee in the department 5 (Logistics). Because of this if we perform inner join, then Department 5 does not appear in the above result. However in the below query we perform an outer join (dept left outer join emp), and we can see this department.

SELECT dept.name DEPARTMENT, emp.name EMPLOYEE 
FROM DEPT dept, EMPLOYEE emp
WHERE dept.id = emp.dept_id (+)