How do you auto increment multiple columns in SQL?
For MyISAM and BDB tables you can specify AUTO_INCREMENT on a secondary column in a multiple-column index. In this case, the generated value for the AUTO_INCREMENT column is calculated as MAX(auto_increment_column) + 1 WHERE prefix=given-prefix . This is useful when you want to put data into ordered groups.
Can you auto increment two columns in MySQL?
For MyISAM tables, you can specify AUTO_INCREMENT on a secondary column in a multiple-column index. In this case, the generated value for the AUTO_INCREMENT column is calculated as MAX( auto_increment_column ) + 1 WHERE prefix= given-prefix . This is useful when you want to put data into ordered groups.
How can use two identity in SQL?
So, no, you can’t have two identity columns. You can of course make the primary key not auto increment (identity). Edit: msdn:CREATE TABLE (Transact-SQL) and CREATE TABLE (SQL Server 2000): Only one identity column can be created per table.
Can we auto increment varchar?
AutoIncrement fields are integer in mysql. You can mirror the auto-increment field in a varchar field and create a trigger which updates the varchar field on insert/update.
How can I get auto increment value after insert?
To obtain the value immediately after an INSERT , use a SELECT query with the LAST_INSERT_ID() function. For example, using Connector/ODBC you would execute two separate statements, the INSERT statement and the SELECT query to obtain the auto-increment value.
Why is auto increment not working?
Basically this is a bug in MySQL that causes the problem but a work around is simple. The problem happens when the Auto-Increment value of a table grows beyond the limit. Just run this SQL query in MySQL to fix the bug. Table_name is the name of the table where you found the error while inserting data into.
How do I create an existing column auto increment in SQL Server?
If you’re looking to add auto increment to an existing table by changing an existing int column to IDENTITY , SQL Server will fight you. You’ll have to either: Add a new column all together with new your auto-incremented primary key, or. Drop your old int column and then add a new IDENTITY right after.
How do I set auto increment to 1?
ALTER TABLE table_name AUTO_INCREMENT = start_value; table_name. The name of the table whose AUTO_INCREMENT value you wish to change. Since a table in MySQL can only contain one AUTO_INCREMENT column, you are only required to specify the table name that contains the sequence.
Can we change column name in SQL?
It is not possible to rename a column using the ALTER TABLE statement in SQL Server. Use sp_rename instead. To rename a column in SparkSQL or Hive SQL, we would use the ALTER TABLE Change Column command.
What does PK mean in database?
Primary key (PK) – value which uniquely identifies every row in the table. Foreign keys (FK) – values match a primary or alternate key inherited from some other table. Alternate Keys (AK) – key associated with one or more columns whose values uniquely identify every row in the table, but which is not the primary key.