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# SQLite expression

An expression is a combination of a plurality of values ​​or SQL functions, operators, and the calculated value.

SQL expressions are similar to formulas, they are written in the query language. You can also use a specific set of data to query the database.

## grammar

SELECT statement in the basic syntax is as follows:

```SELECT column1, column2, columnN
FROM table_name
WHERE [CONTION | EXPRESSION];
```

There are different types of SQLite expression, specifically explain as follows:

## SQLite - Boolean expression

SQLite Boolean expressions to obtain data on the basis of matching the individual values. The syntax is as follows:

```SELECT column1, column2, columnN
FROM table_name
WHERE SINGLE VALUE MATCHTING EXPRESSION;
```

Suppose COMPANY table has the following records:

```ID NAME AGE ADDRESS SALARY
---------- ---------- ---------- ---------- ----------
1 Paul 32 California 20000.0
2 Allen 25 Texas 15000.0
3 Teddy 23 Norway 20000.0
4 Mark 25 Rich-Mond 65000.0
5 David 27 Texas 85000.0
6 Kim 22 South-Hall 45000.0
7 James 24 Houston 10000.0
```

The following example demonstrates the use of Boolean expressions SQLite:

```sqlite> SELECT * FROM COMPANY WHERE SALARY = 10000;
---------- ---------- ---------- ---------- ----------
4 James 24 Houston 10000.0
```

## SQLite - a numeric expression

These expressions are used to execute queries for any math. The syntax is as follows:

```SELECT numerical_expression as OPERATION_NAME
[FROM table_name WHERE CONDITION];
```

Here, numerical_expression any mathematical expression or formula used. The following example demonstrates the use SQLite numeric expression:

```sqlite> SELECT (15 + 6) AS ADDITION
```

There are several built-in functions, such as avg (), sum (), count (), etc., it is called Executive summary data for a table or a specific table column calculations.

```sqlite> SELECT COUNT (*) AS "RECORDS" FROM COMPANY;
RECORDS = 7
```

## SQLite - date expression

Date expression that returns the current system date and time values, these expressions will be used for a variety of data manipulation.

```sqlite> SELECT CURRENT_TIMESTAMP;
CURRENT_TIMESTAMP = 2013-03-17 10:43:35
```