Query Issues

Dear Experts,

Can u please help me below mentioned Issues

1.How can i know the Individual Query run time ?and how can i improve it?

2.Wht is the use of statistics cubes?how can i activate it and wht are the precautions to take when activating statistic cubes

3.How can i know that which query is using by which end user,

so that i can know how frequently they are using reports.

Thanks&Regards

Seshagiri

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