注意:在实际应用中,聚合函数常和分组函数group by结合使用,用来查询.where 子句的作用对象一般只是行,用来作为过滤数据的条件。 其他聚合函数(aggregate function) 6、 count_big()返回指定组中的项目数量。 与count()函数区别:count_big()返回bigint值,而count()返回的是int值。 数据类型
An aggregate function is a function that performs a calculation on a set of values, and returns a single value. Aggregate functions are often used with theGROUP BYclause of theSELECTstatement. TheGROUP BYclause splits the result-set into groups of values and the aggregate function can be used...
AVG：计算指定列的平均值，即所有值的总和除以行数。COUNT：返回某列中非NULL值的行数。COUNT：统计被选行的总数，包括所有行，不考虑列值是否为NULL。FIRST：返回指定列中的第一个非NULL值，但请注意，并非所有SQL版本都支持此函数。LAST：返回指定列中的最后一个非NULL值，同样，部分SQL版本不支持此...
approx_percentile_cont_with_weight General aggregate functions array_agg avg array_agg Returns an array created from the expression elements. array_aggreturns aLISTarrow type. Use bracket notation to reference the index of an element in the returned array. Arrays are 1-indexed. array_agg(expressio...
Common Aggregate Window Functions In this tutorial, we'll explore the 7 commonly used SQL Aggregate Window Functions: COUNT() counts the number of rows in a specified column across a defined window. SUM() computes the sum of values within a specified column across a defined window. AVG() ca...
The OVER clause may follow all aggregate functions, except the STRING_AGG, GROUPING or GROUPING_ID functions.Use aggregate functions as expressions only in the following situations:The select list of a SELECT statement (either a subquery or an outer query). A HAVING clause.Transact-SQL provides ...
Introduction to built-in functions Aggregate functions Introduction to aggregate functions ANY_VALUE ARRAY_AGG AVG COUNT MAP_AGG MAX MIN SUM STDEV STDEVP VAR VARP Analytics functions Metadata functions Ranking functions User-defined operators Built-in system objects and extensions Control-of-flow language...
The OVER clause may follow all aggregate functions except GROUPING and GROUPING_ID. Aggregate functions can be used as expressions only in the following: The select list of a SELECT statement (either a subquery or an outer query). A HAVING clause. Transact-SQL provides the following aggregate ...
The LISTAGG function aggregates a set of strings into one string by concatenating the strings. Optionally, a separator string can be provided which is inserted between contiguous input strings.
Functions ODBC Scalar Aggregate Aggregate APPROX_COUNT_DISTINCT APPROX_PERCENTILE_CONT APPROX_PERCENTILE_DISC AVG CHECKSUM_AGG COUNT COUNT_BIG GROUPING GROUPING_ID MAX MIN PRODUCT STDEV STDEVP SUM VAR VARP AI Analytic Bit manipulation Collation