date_add()函数自定义

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由于，人大金仓数据库kingbase不兼容MySQL数据库的date_add()函数，要自定义一个，求大神指点！！！

[Hello World,]

试下： date now() + integer '1'

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需求要使用date_add函数，kingbase不兼容，要自己创建一个

[Hello World,]

那就先创建一个函数再调用，参考 服务器编程->SQL语句参考手册 CREATE FUNCTION 概述 CREATE FUNCTION -- 定义一个新函数 语法格式 CREATE [ OR REPLACE ] [ INTERNAL ] FUNCTION name ( [ [ argmode ] [ argname ] argtype [ { DEFAULT | := } default_expr ] [, ...] ] ) [ { RETURNS | RETURN } rettype | { RETURNS | RETURN } TABLE ( column_name column_type [, ...] ) ] { LANGUAGE lang_name | TRANSFORM { FOR TYPE type_name } [, ... ] | WINDOW | IMMUTABLE | STABLE | VOLATILE | [ NOT ] LEAKPROOF | CALLED ON NULL INPUT | RETURNS NULL ON NULL INPUT | STRICT | [ EXTERNAL ] SECURITY INVOKER | [ EXTERNAL ] SECURITY DEFINER | PARALLEL { UNSAFE | RESTRICTED | SAFE } | COST execution_cost | ROWS result_rows | SET configuration_parameter { TO value | = value | FROM CURRENT } | { AS | IS } 'definition' | { AS | IS } 'obj_file', 'link_symbol' } ... [ WITH ( attribute [, ...] ) ] 兼容Oracle语法： CREATE [ OR REPLACE ] FUNCTION name ( [ [ argmode ] [ argname ] argtype [ { DEFAULT | := } default_expr ] [, ...] ] )[{RETURNS | RETURN} rettype ] [IMMUTABLE | STABLE | VOLATILE | SECURITY INVOKER | SECURITY DEFINER] { AS | IS } { [ label_name ] [ DECLARE ] [ variable_declaration ] [ cursor_declaration ] BEGIN sequence_of_statement END [ label_name ] }