REGR_SXX makes the following computation after eliminating NULL (expr1, expr2) pairs:
REGR_COUNT(expr1, expr2) * VAR_POP(expr2)
The function returns a value of type NUMERIC. If the function is applied to an empty set, then it returns null.
VAR()
VAR_SAMP()
VAR_POP()
STDDEV()
STDDEV_SAMP()
STDDEV_POP()
REGR_SYY()
REGR_SXX()
REGR_SXY()
REGR_AVGX()
REGR_AVGY()
REGR_R2()
REGR_COUNT()
REGR_INTERCEPT()
REGR_SLOPE()
COVAR_SAMP()
COVAR_POP()
CORR()