Show 13.1.9 ALTER TABLE Statement
There are several additional aspects to the
Table Options For descriptions of all table options, see Section 13.1.20, “CREATE TABLE Statement”. However, Use of table options with
To verify that the table options were changed as intended, use
Performance and Space Requirements
For tables
using the
See Section 23.6.11, “Online Operations with ALTER TABLE in NDB Cluster”, for more information. The Specifying an
The exception referred to earlier is that An To force use of the For For information about space requirements for online DDL operations, see Section 15.12.3, “Online DDL Space Requirements”.
For more information about operations that support
If an The NDB Cluster 8.0 supports online operations using the same NDB 8.0.27 and later, when performing a copying For Concurrency Control For Only The parameters for the
Adding and Dropping Columns Use To add a column at a specific position within a table row, use If a table contains only one column, the column cannot be dropped. If what you intend is to remove the table, use the If columns are dropped from a table, the columns are also removed from any index of which they are a part. If all columns that make up an index are dropped, the index is dropped as well. If you use For Renaming, Redefining, and Reordering Columns The
To alter a column to change both its name and definition, use
To change a column definition but not its name, use
To change a column name but not its definition, use
In general, you cannot rename a column to a name that already exists in the table. However, this is sometimes not the case, such as when you swap names or move them through a cycle. If a table has columns named
For column definition changes using
That statement changes the data type from
For data type changes using Warning This conversion may result in alteration of data. For example, if you shorten a string column, values may be truncated. To prevent the operation from succeeding if conversions to the new data type would result in
loss of data, enable strict SQL mode before using If you use For columns renamed by
For columns renamed by
To reorder columns within a table, use As of MySQL 8.0.23, Primary Keys and Indexes If the If you add a Some storage engines permit you to specify an index type when creating an index. The syntax for the If you use For While the nonunique
indexes are disabled, they are ignored for statements such as After an The Foreign Keys and Other Constraints The For
Important MySQL
silently ignores inline MySQL Server and NDB Cluster both support the use of
Adding and dropping a foreign key in the same
The server prohibits changes to foreign key columns
that have the potential to cause loss of referential integrity. A workaround is to use
Prior to MySQL 8.0.16,
As of MySQL 8.0.16,
The As of MySQL 8.0.19,
The SQL standard specifies that all types of constraints (primary key, unique index, foreign key, check) belong to the same namespace. In MySQL, each constraint type has its own namespace per schema. Consequently, names for each type of constraint must be unique per schema, but constraints of different types can have the same name. When multiple constraints have the same name, If a table alteration causes a violation of an enforced
Changing the Character Set To change the table default character set and all character columns
(
The statement also changes the collation
of all character columns. If you specify no For a column that has a data type of
To avoid data type changes of the type just described, do not use
If you specify If Warning The
The reason this works is that there is no conversion when you convert to or from To change only the default character set for a table, use this statement:
The word When the Importing InnoDB Tables An Row Order for MyISAM Tables Note The table does not remain in the specified order after inserts and deletes. When used on a partitioned table,
Partitioning Options It is possible for an For more information about partition options, see
Section 13.1.20, “CREATE TABLE Statement”, and Section 13.1.9.1, “ALTER TABLE Partition Operations”. For information about and examples of How do I replace one column in SQL?Syntax. Syntax. SELECT REPLACE('DEFULTSFFG','HIJ','KLM'); GO.. This example selects and replaces all the data.. Example.. The following example Selects and Replaces all the data.. The following example uses the Collection function in Replace statement.. Syntax. SELECT REPLACE('This is a Sample' COLLATE Latin1_General_BIN,. How do you replace something in MySQL?MySQL REPLACE() Function
The REPLACE() function replaces all occurrences of a substring within a string, with a new substring. Note: This function performs a case-sensitive replacement.
How do I change one column to another column in MySQL?To update one column data to another column, you can use UPDATE command. Let us check the column UserFirstName is updated or not.
How can I replace part of a string in MySQL?Use the MySQL REPLACE() function to replace a substring (i.e. words, a character, etc.) with another substring and return the changed string.. The string to change. ... . The substring to replace (i.e. the character '-').. The substring to insert (i.e. the character '/').. |