Postgresql function return json1/22/2024 Will require effort proportional to the size of the table: PostgreSQL will need to scan either the entire table or the entirety of an index which includes all rows in the table. Users accustomed to working with other SQL database management systems might be disappointed by the performance of the count aggregate when it is applied to the entire table. ![]() The coalesce function can be used to substitute zero or an empty array for null when necessary.Īggregate functions which support Partial Mode are eligible to participate in various optimizations, such as parallel aggregation. In particular, sum of no rows returns null, not zero as one might expect, and array_agg returns null rather than an empty array when there are no input rows. It should be noted that except for count, these functions return a null value when no rows are selected. Sum of expression across all non-null input valuesĬoncatenation of non-null XML values (see also Section 9.14.1.7) Smallint, int, bigint, real, double precision, numeric, interval, or moneyīigint for smallint or int arguments, numeric for bigint arguments, otherwise the same as the argument data type Non-null input values concatenated into a string, separated by delimiter Minimum value of expression across all non-null input values Maximum value of expression across all non-null input values Number of input rows for which the value of expression is not nullĪggregates values, including nulls, as a JSON arrayĪggregates name/value pairs as a JSON object values can be null, but not namesĪny numeric, string, date/time, network, or enum type, or arrays of these types True if at least one input value is true, otherwise false True if all input values are true, otherwise false The bitwise OR of all non-null input values, or null if none The bitwise AND of all non-null input values, or null if none The average (arithmetic mean) of all non-null input values Numeric for any integer-type argument, double precision for a floating-point argument, otherwise the same as the argument data type Smallint, int, bigint, real, double precision, numeric, or interval ![]() Input arrays concatenated into array of one higher dimension (inputs must all have same dimensionality, and cannot be empty or null) Input values, including nulls, concatenated into an array
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