bit Datatype

Use the bit datatype for columns that contain true/false and yes/no types of data. The status column in the syscolumns system table indicates the unique offset position for bit datatype columns.

bit columns hold either 0 or 1. Integer values other than 0 or 1 are accepted, but are always interpreted as 1.

Storage size is 1 byte. Multiple bit datatypes in a table are collected into bytes. For example, 7 bit columns fit into 1 byte; 9 bit columns take 2 bytes.

Columns with a datatype of bit cannot be NULL and cannot have indexes on them.

The bit datatype is a Transact-SQL extension.