mysql not null default

One of my coworkers came across a strange quirk in MySQL with default value...

One of my coworkers came across a strange quirk in MySQL with default values for not null columns. Take a look at this table.

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NULLs have special behavior: comparing anything with a NULL gives you back ...

NULLs have special behavior: comparing anything with a NULL gives you back a NULL, which is something else than false or 0. It means.

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You should remove DEFAULT: ALTER TABLE tblechecklistrevision ADD COLUMN IWo...

You should remove DEFAULT: ALTER TABLE tblechecklistrevision ADD COLUMN IWorkFlowOrder INT(10) NOT NULL AFTER fState;.

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This is because the table already has a row or more with null value, you mi...

This is because the table already has a row or more with null value, you might need to update those to 0 before executing ALTER table, e.g.

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DEFAULT is the value that will be inserted in the absence of an explicit va...

DEFAULT is the value that will be inserted in the absence of an explicit value in an insert / update statement. Lets assume, your DDL did not.

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ALTER TABLE table1 ADD COLUMN foo INT DEFAULT 0; ALTER TABLE `tablename` AD...

ALTER TABLE table1 ADD COLUMN foo INT DEFAULT 0; ALTER TABLE `tablename` ADD `new_col_name` INT NOT NULL DEFAULT 0;.

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In most DBs a NOT NULL column will be more efficient in terms of stored dat...

In most DBs a NOT NULL column will be more efficient in terms of stored data for the reason you state, and also more efficient to query and.

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In MySQL, the ALTER COLUMN subclause can only be used for setting or droppi...

In MySQL, the ALTER COLUMN subclause can only be used for setting or dropping the default value of the column (SET DEFAULT literal ALTER TABLE MyTable CHANGE COLUMN comment comment BIGINT NOT NULL;.

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Create table: not null and default value /* mysql> Drop table Product; Q...

Create table: not null and default value /* mysql> Drop table Product; Query OK, 0 rows affected ( sec) mysql> CREATE TABLE Product -> (-> ID SMALLINT.

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Generally, the NULL value makes your queries more complicated. In such case...

Generally, the NULL value makes your queries more complicated. In such cases, you can use the NOT NULL constraint and provide a default value for the.

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The MySQL CREATE TABLE statement allows you to create and define a table. C...

The MySQL CREATE TABLE statement allows you to create and define a table. CREATE TABLE table_name (column1 datatype [ NULL | NOT NULL ], column2 value | MIN_ROWS = value | PACK_KEYS = {0 | 1 | DEFAULT} | PASSWORD.

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Having NOT NULL columns permits similar performance on MySQL Just avoid the...

Having NOT NULL columns permits similar performance on MySQL Just avoid the default setting that allows NULL values in every column.

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Here is my advice on Not Null for all RDBMS. Every column should have the N...

Here is my advice on Not Null for all RDBMS. Every column should have the Not Null constraint unless there is a good reason for allowing null. I.e., the default in.

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In MySQL a NOT NULL int with no default value has not a default value. For ...

In MySQL a NOT NULL int with no default value has not a default value. For an int value to have a default value of 0 you need to explicitly write.

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For example, a primary key might now be described as client_id SMALLINT(3) ...

For example, a primary key might now be described as client_id SMALLINT(3) UNSIGNED NOT NULL and Default Values NULL.

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