# What is a computed column in SQL Server?

**computed column**is a virtual

**column**that is not physically stored in the table, unless the

**column**is marked PERSISTED. A

**computed column**expression can use data from other

**columns**to

**calculate**a value for the

**column**to which it belongs.

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Simply so, is persisted in SQL computed column meaning?

**Computed columns** can be **persisted**. It **means** that **SQL** Server physically stores the data of the **computed columns** on disk. When you change data in the table, **SQL** Server computes the result based on the expression of the **computed columns** and stores the results in these **persisted columns** physically.

One may also ask, what does persisted mean in SQL? **PERSISTED**. Specifies that the Database Engine will physically store the computed values in the table, and update the values when any other columns on which the computed column depends are updated.

Secondly, how do you make a calculation in SQL?

When you need to **perform calculations in SQL** statement, you use arithmetic expression. An arithmetic expression can contain column names, numeric numbers, and arithmetic operators.

Operator | Description |
---|---|

+ | Addition operator |

- | Minus operator |

* | Multiplication operator |

/ | Division operator |

Which comparison operators can you use in a where clause?

Comparison operators are used to test the equality of two input expressions. They are typically used in the WHERE clause of a **query**. a is equal to b .