Translation: last_value () function (submitted to the MariaDB official Manual), last_valuemariadb

Translation: last_value () function (submitted to the MariaDB official Manual), last_valuemariadb

This article is the translation of LAST_VALUE () in mariadb's official manual.

Original article: https://mariadb.com/kb/en/last_value/
Https://mariadb.com/kb/zh-cn/last_value/ I submitted to the MariaDB official manual

Syntax

LAST_VALUE(expr,[expr,...])

Description

LAST_VALUE()Evaluate all expressions and return the last value.

This is useful when @ var: = expr is used in combination to assign values to variables. For example, if you want to retrieve data from the updated/deleted row, you do not need to perform two queries on the table.

From MariaDB 10.2.2, LAST_FUNCTION can be used as a window function.

Example

Create table t1 (a int, B int); INSERT INTO t1 VALUES (1, 10), (2, 20); DELETE FROM t1 WHERE a = 1 AND last_value (@ a: =, @ B: = B, 1); SELECT @ a, @ B; + ------ + | @ a | @ B | + ------ + | 1 | 10 | + ------ + // The translator adds the example DELETE FROM t1; insert into t1 VALUES (), (), (); delete from t1 WHERE a = 1 AND last_value (@ a: = a, @ B: = B, 1); SELECT *, @ a, @ B; + ------ + | a | B | @ a | @ B | + ------ + | 2 | 20 | 1 | 30 | + ------ + ------ +

 

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