PostgreSQL的if判断语句 

 1 PostgreSQL if判断语句
 2 1、语法：
 3 if condition then
 4     statement;
 5 end if;
 6 
 7 案例1：
 8 do $$
 9 declare 
10     a integer := 10;
11     b integer := 20;
12 begin 
13     if a>b then 
14         raise notice 'a is greater then b';
15     end if;
16     
17     if a<b then 
18         raise notice 'a is less then b';
19     end if;
20     
21     if a=b then
22         raise notice 'a is equal to b ';
23     end if;
24 end; $$
25 
26 
27 
28 2、语法：
29 if then else
30 if condition then
31     statement1;
32 else
33     statement2;
34 end if;
35 
36 案例：
37 do $$
38 declare 
39     a integer :=10;
40     b integer :=20;
41 begin 
42     if a > b then 
43         raise notice 'a is greater then b';
44     else 
45         raise notice 'a is not greater then b';
46     end if;
47 
48 end; $$
49 
50 
51 
52 3、语法：
53 if condition then 
54     statement1;
55 elsif condition then 
56     statement2;
57     ...
58 else
59     statementn;
60 end if;
61 
62 案例：
63 do $$
64 declare
65     a integer :=20;
66     b integer :=20;
67 begin
68     if a > b then 
69         raise notice 'a is greater then b';
70     elsif a = b then 
71         raise notice 'a is equal to b';
72     elsif a < b then
73         raise notice 'a is less then b';
74     else
75         raise notice 'error';
76     end if;
77 end; $$

 

posted @ 2022-07-13 16:04  Thenext  阅读(10919)  评论(0)    收藏  举报