postgres function: COALESCE_func.coalesce

COALESCE

 
COALESCE(value [, ...])

The COALESCE function returns the first of its arguments that is not null. Null is returned only if all arguments are null. It is often used to substitute a default value for null values when data is retrieved for display, for example:

SELECT COALESCE(description, short_description, '(none)') ...

Like a CASE expression, COALESCE only evaluates the arguments that are needed to determine the result; that is, arguments to the right of the first non-null argument are not evaluated. This SQL-standard function provides capabilities similar to NVL and IFNULL, which are used in some other database systems.

TD中zeroifnull函数可用本函数替代：coalesce(arg,0)，在notepad++中替换的正则表达式：

将

zeroifnull$([\s\w\.]+)$

替换为：

COALESCE(\1,0)