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# SQLite Expressions An expression is a combination of one or more values, operators, and SQL functions that compute a value. SQL expressions are similar to formulas and are written in the query language. You can also use specific datasets to query the database. ## Syntax Assume the basic syntax of the SELECT statement is as follows: SELECT column1, column2, columnN FROM table_name WHERE [CONDITION | EXPRESSION]; There are different types of SQLite expressions, which are explained in detail below: ## SQLite - Boolean Expressions SQLite Boolean expressions fetch data based on matching a single value. The syntax is as follows: SELECT column1, column2, columnN FROM table_name WHERE SINGLE VALUE MATCHING EXPRESSION; Assume the COMPANY table has the following records: ID NAME AGE ADDRESS SALARY ---------- ---------- ---------- ---------- ----------1 Paul 32 California 20000.02 Allen 25 Texas 15000.03 Teddy 23 Norway 20000.04 Mark 25 Rich-Mond 65000.05 David 27 Texas 85000.06 Kim 22 South-Hall 45000.07 James 24 Houston 10000.0 The following example demonstrates the usage of SQLite Boolean expressions: sqlite> SELECT * FROM COMPANY WHERE SALARY = 10000; ID NAME AGE ADDRESS SALARY ---------- ---------- ---------- ---------- ----------4 James 24 Houston 10000.0 ## SQLite - Numeric Expressions These expressions are used to perform any mathematical operations in a query. The syntax is as follows: SELECT numerical_expression as OPERATION_NAME ; Here, numerical_expression is used for mathematical expressions or any formulas. The following example demonstrates the usage of SQLite numeric expressions: sqlite> SELECT (15 + 6) AS ADDITION ADDITION = 21 There are several built-in functions, such as avg(), sum(), count(), etc., to perform what is known as aggregate data calculations on a table or a specific table column. sqlite> SELECT COUNT(*) AS "RECORDS" FROM COMPANY; RECORDS = 7 ## SQLite - Date Expressions Date expressions return the current system date and time values. These expressions are used for various data manipulations. sqlite> SELECT CURRENT_TIMESTAMP; CURRENT_TIMESTAMP = 2013-03-17 10:43:35