如何在 postgresql 中为空单元格设置 IsNullOrEmpty 条件？

Question

我的成绩是 A table

    id          |   Marks
----------------+----------
    1           |    
    2           |    33

for record in (select Marks from grades)
loop
 marks=rec.Marks;
 if(marks is null) then
   marks=0; 
 end if;
end loop;

My Problem is in if condition how to write the condition for marks is null, marks is a integer type

Answer 1

要更改值，请使用 update 语句：

update grades
  set marks = 0
where marks is null;

要插入数据，请使用带有合并的 insert 语句：

insert into temp_table (col1, marks)
select col1, coalesce(marks, 0)
from grades;

Answer 2

如果您想在检索时更改此设置，您还可以使用 CASE 或 COALESCE

SELECT col1, COALESCE(marks, 0) as MARKS from grades

或

SELECT col1, CASE WHEN marks IS NULL THEN 0 ELSE marks END AS marks
  FROM grades

如何在 postgresql 中为空单元格设置 IsNullOrEmpty 条件？

How Can I Make the Condition For IsNullOrEmpty for Empty cell in postgresql?

postgresql-9.1