We call each row in the table a "record", and each record contains all the information in this row, just like in themail listAll the information of a person in the database, but the record has no special record name in the database. The number of rows it is in is often used to indicate the number of records.A field is a smaller unit than a record. A set of fields constitutes a record. Each field describes a certain feature of a document, that isdata item, and there is a uniqueField Identifier。
A member that represents a variable associated with an object or class.
In most databases, the "column" of a table is called "field", and each field contains information about a certain topic.Just like in the "Address Book" database, "Name"“contact number”These are common attributes of all rows in the table, so these columns are called "Name" fields and "Contact Phone" fields.
Sometimes, however, a field is not a column in a table. For example, as is used to calculate the content of a column and "store" it in another field.For example, a table "T" has only column "ID", and the content is "int" value "1".Application“selectid, id * 5 as abc from T ", the result is
id abc
1 5
Other information
Announce
edit
This SQL statement has been tested without error in MYSQL 5.0.
