[@CAVG(..., C) -] Conditional average.
[@CCOUNT(..., C) -]Conditional count.
[@CMAX(..., C) -] Conditional maximum.
[@CMIN(..., C) -] Conditional minimum.
[@CSTD(..., C) -] Conditional sample standard deviation (N weighting).
[@CSTDS(..., C) -] Conditional sample standard deviation (N-1 weighting).
[@CSUM(..., C) -] Conditional sum.
[@CVAR(..., C) -] Conditional population variance (N weighting).
[@CVARS(..., C) -] Conditional population variance (N-1 weighting).