PostgreSQL 中“IF”或附近的语法错误

Question

我正在尝试在 PostgreSQL 上编写 sql function，但我的“IF”有错误：

ERROR: Syntax error at or near "IF"
LINE 11: IF Type = 's' THEN

我无法理解语法错误。
（没有中频的Function工作正常）

我的 SQL 代码：

CREATE OR REPLACE FUNCTION public.add_activity(IDactivity smallint,Date_Start date, Data_End date, 
Type character varying,Name character varying DEFAULT NULL::character varying,
Typology character varying DEFAULT NULL::character varying, Client smallint DEFAULT NULL::smallint)
RETURNS void
LANGUAGE 'sql'
AS $BODY$

INSERT INTO public."Activity" 
VALUES(IDactivity, Date_Start, Data_End, Type, Name);

IF Type = 's' THEN
INSERT INTO public."Service" 
VALUES(IDactivity, Typology, Client); 

END IF;
$BODY$;

谢谢！

Answer 1

IF未在sql语言中实现，但在plpgsql语言中实现，请参阅手册。

您可以将LANGUAGE sql替换为LANGUAGE plpgsql ，然后在 function 正文中添加BEGIN和END ：

CREATE OR REPLACE FUNCTION public.add_activity(IDactivity smallint,Date_Start date, Data_End date, 
Type character varying,Name character varying DEFAULT NULL::character varying,
Typology character varying DEFAULT NULL::character varying, Client smallint DEFAULT NULL::smallint)
RETURNS void
LANGUAGE plpgsql
AS $BODY$
BEGIN
INSERT INTO public."Activity" 
VALUES(IDactivity, Date_Start, Data_End, Type, Name);

IF Type = 's' THEN
INSERT INTO public."Service" 
VALUES(IDactivity, Typology, Client); 
END IF;

END ;
$BODY$

或者您可以更改您的代码以保持sql语言：

CREATE OR REPLACE FUNCTION public.add_activity(IDactivity smallint,Date_Start date, Data_End date, 
Type character varying,Name character varying DEFAULT NULL::character varying,
Typology character varying DEFAULT NULL::character varying, Client smallint DEFAULT NULL::smallint)
RETURNS void
LANGUAGE sql
AS $BODY$

INSERT INTO public."Activity" 
VALUES(IDactivity, Date_Start, Data_End, Type, Name);

INSERT INTO public."Service"
SELECT IDactivity, Typology, Client
WHERE Type = 's' ;

$BODY$