{ REGR_SLOPE 
| REGR_INTERCEPT 
| REGR_COUNT 
| REGR_R2 
| REGR_AVGX
| REGR_AVGY 
| REGR_SXX 
| REGR_SYY 
| REGR_SXY
}
( expr1 , expr2 ) [OVER ( analytic_clause )]