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When to use null as default in MySQL?
When I run alter table query it get success but still on new row insertion table consider NULL as default value if column value is not specified. Blob and text columns cannot have a DEFAULT value ( Ref ). Depending on platform, MySQL may generate a warning or error when you try to do that.
How to change the default column in MySQL?
Alter table structure using the following query USE MODIFY ALTER TABLE MODIFY VARCHAR ( ) DEFAULT ”; Thanks for contributing an answer to Stack Overflow!
Why does MySQL not have default value for COL2?
The error message is: BLOB, TEXT, GEOMETRY or JSON column ‘col2’ can’t have a default value. Reference Good Read: Why can’t a text column have a default value in MySQL?
How to change default column in phpMyAdmin?
In phpmyadmin go to “change” option for specific Field and select Default2 as As defined: and leave below text box empty Alter table structure using the following query USE MODIFY ALTER TABLE MODIFY VARCHAR ( ) DEFAULT ”;
How to return an empty string in MySQL?
If expr1 is not NULL, IFNULL () returns expr1; otherwise it returns expr2. If you really must output every values including the NULL ones: Coalesce will return the first non-null argument passed to it from left to right. If all arguemnts are null, it’ll return null, but we’re forcing an empty string there, so no null values will be returned.
Is there a way to return NULL in SQL?
If all arguemnts are null, it’ll return null, but we’re forcing an empty string there, so no null values will be returned. Also note that the COALESCE operator is supported in standard SQL. This is not the case of IFNULL. So it is a good practice to get use the former.
Is there a default value for inserting nulls in SQL?
This makes it work NO MATTER what code tries to insert NULLs into your table, avoids stored procedures, is completely transparent, and you only need to maintain your default values in one place, namely this trigger. You can use the COALESCE function in MS SQL.