如何修改varchar的大小？

Question

I need to know if there is any way i can modify the size of a varchar from varchar(40) to varchar(60) and also add this constraint:

(( CASE WHEN DATEDIFF(day,Date_Election_President,CURRENT_TIMESTAMP) >= 730 THEN
             'NON'
        ELSE 'OUI'
   END ))

Answer 1

To change the length;

ALTER TABLE [MyTable]
ALTER COLUMN [MyColumn] VARCHAR(60)

As to the constraint, I suspect you're looking for a computed column. You should be able to add it like this;

ALTER TABLE [MyTable] 
ADD [NewColumn] AS CASE 
   WHEN DATEDIFF(day,Date_Election_President,CURRENT_TIMESTAMP) >= 730 THEN 'NON' 
   ELSE 'OUI' 
END

Demo here .

Answer 2

Use this Query and run it on query board

ALTER TABLE [TableName] 
ALTER COLUMN [ColumnName] VARCHAR(60)