Tracking: mathematical functions

[xiangjinwu]

https://www.postgresql.org/docs/current/functions-math.html

Make sure to test special values: -inf, inf, nan for decimal / real / double, and -0 for real / double.

proto ExprType 213, 214, 219, 221, 222, 233, 234, 245..=267, 401..=419

Cast

• implicit: smallint -> int -> bigint -> decimal -> real -> double
• assign: double -> real -> decimal -> bigint -> int -> smallint

Polymorphic

• unary + / - for smallint / int / bigint / decimal / real / double
• @ / abs for smallint / int / bigint / decimal / real / double
• binary + / - / / / * for various combinations
• % / mod for smallint / int / bigint / decimal
• gcd / lcm for int / bigint / decimal
• ~ / & / | / # for smallint / int / bigint
• << / >> for lhs smallint / int / bigint

Formatting

• to_char / to_number in Tracking: string and bytea functions #8831

For decimal and double

• round / trunc / ceil / ceiling / floor
• Implement the sign function #8900
• Implement sqrt function #8899
• Implement exp / ln / log / log10 (missing decimal / ln / log / log10) #8903
• ^ / pow / power Implement exp/pow function #7725
• width_bucket(operand, low, high, count)

For decimal

• factorial(bigint) -> decimal
• div(decimal, decimal) -> decimal
• log(decimal, decimal) -> decimal support log(b decimal, x decimal) function which is the logarithm to base b #13150
• round(decimal, int) -> decimal
• trunc(decimal, int) -> decimal
• min_scale(decimal) -> int
• scale(decimal) -> int
• trim_scale(decimal) -> decimal

For double

• ||/ / cbrt
• Implement degrees / radians #8901
• pi
• Implement sin / cos / tan / cot / asin / acos / atan / atan2
• implement sind / cosd / tand / cotd / asind / acosd / atand / atan2d #9678
• Implement functions: sinh / cosh / tanh / asinh / acosh / atanh #9675

Aggregate Functions

• sum
  • smallint / int -> bigint
  • bigint / decimal -> decimal
  • real -> real
  • double -> double
• avg
  • smallint / int / bigint / decimal -> decimal
  • real / double -> double
• implement bit_and / bit_or / bit_xor for smallint / int / bigint #9281
• Support agg function stddev_samp and stddev_pop #7559
• Support agg function variance_samp and variance_pop #7647
• covar_pop / covar_samp
• corr
• regr_avgx / regr_avgy / regr_count / regr_intercept / regr_r2 / regr_slope / regr_sxx / regr_sxy / regr_syy

Set Returning Functions

• generate_series(start, stop [, step]) for int / bigint / numeric bug(frontent): generate_series not compatible with PSQL  #8826

Impure

• random / setseed

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