The difference is that WHERE operates on individual rows, while HAVING operates on groups.
You can have WHERE without HAVING, you can have HAVING without WHERE, you can have both WHERE and HAVING, and you can have neither WHERE nor HAVING. But you can't have HAVING without grouping, even if the group consists of the entire result set.
In SQL, the having clause and the group by statement work together when using aggregate functions like SUM, AVG, MAX, etc. This is best illustrated by an example. Suppose we have a table called emp_bonus as shown below. Note that the table hasmultiple entries for employees A and B.
If we want to calculate the total bonus that each employee received, then we would write a SQL statement like this:
Talend Open Studio operates as a code generator allowing data transformation scripts and underlying programs to be generated either in Java (OR) Perl. Its GUI is made of a metadata repository and a graphical designer. The metadata repository contains the definitions and configuration for each job. The information in the metadata repository is used by all of the components of Talend Open Studio.