A SAS data set is exactly equivalent to the concept of a table (formally, a. âtupleâ) in the relational model. The programmer could use either data step MERGE or use a join. in PROC SQL. Which one to use can be a matter of personal preference. But if you learn each. method well, you can choose the best tool for each specific situation.
An eye twitch is an involuntary spasm of the muscles in the eyelid. Blepharospasm is the medical term for eyelid twitching. Eyelid twitching usually occurs every few seconds and lasts for a few minutes. It may come and go over a period of days or weeks. Sometimes the twitching results in the eye being held closed until the movement stops, but this is not always the case.
What you may be experiencing is an eyelid twitch. A âtwitchâ is the common term used for an involuntary, repetitive spasm or a contraction of the involved muscles. During eye twitching, the eyelid may open and close involuntarily. Although puzzling, twitches occur often and affect millions of people every year.