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  2. Group by (SQL) - Wikipedia

    en.wikipedia.org/wiki/Group_by_(SQL)

    This implies constraints on the columns that can appear in the associated SELECT clause. As a general rule, the SELECT clause may only contain columns with a unique value per group. This includes columns that appear in the GROUP BY clause as well as aggregates resulting in one value per group. [3]

  3. Carry (arithmetic) - Wikipedia

    en.wikipedia.org/wiki/Carry_(arithmetic)

    In elementary arithmetic, a carry is a digit that is transferred from one column of digits to another column of more significant digits. It is part of the standard algorithm to add numbers together by starting with the rightmost digits and working to the left. For example, when 6 and 7 are added to make 13, the "3" is written to the same column ...

  4. Digital sum in base b - Wikipedia

    en.wikipedia.org/wiki/Digital_sum_in_base_b

    More usually the digital sum is calculated in binary (base 2) where the result only depends upon whether there are an even or odd number of 1s in each column. This is the same function as parity or multiple exclusive ors. For example: 011 (3) 100 (4) 101 (5) --- 010 (2) is the binary digital sum of 3, 4 and 5.

  5. Matrix addition - Wikipedia

    en.wikipedia.org/wiki/Matrix_addition

    Two matrices must have an equal number of rows and columns to be added. [1] In which case, the sum of two matrices A and B will be a matrix which has the same number of rows and columns as A and B. The sum of A and B, denoted A + B, is computed by adding corresponding elements of A and B: [2] [3]

  6. Summation - Wikipedia

    en.wikipedia.org/wiki/Summation

    In mathematics, summation is the addition of a sequence of numbers, called addends or summands; the result is their sum or total.Beside numbers, other types of values can be summed as well: functions, vectors, matrices, polynomials and, in general, elements of any type of mathematical objects on which an operation denoted "+" is defined.

  7. Ramanujan summation - Wikipedia

    en.wikipedia.org/wiki/Ramanujan_summation

    Ramanujan summation is a technique invented by the mathematician Srinivasa Ramanujan for assigning a value to divergent infinite series.Although the Ramanujan summation of a divergent series is not a sum in the traditional sense, it has properties that make it mathematically useful in the study of divergent infinite series, for which conventional summation is undefined.

  8. Divisor sum identities - Wikipedia

    en.wikipedia.org/wiki/Divisor_sum_identities

    Let the function () denote the characteristic function of the primes, i.e., () = if and only if is prime and is zero-valued otherwise. Then as a special case of the first identity in equation (1) in section interchange of summation identities above, we can express the average order sums

  9. SQL - Wikipedia

    en.wikipedia.org/wiki/SQL

    SQL was initially developed at IBM by Donald D. Chamberlin and Raymond F. Boyce after learning about the relational model from Edgar F. Codd [12] in the early 1970s. [13] This version, initially called SEQUEL (Structured English Query Language), was designed to manipulate and retrieve data stored in IBM's original quasirelational database management system, System R, which a group at IBM San ...