WHERE Clause

SQLite WHERE clause is used to specify a condition while fetching the data from one table or multiple tables.

If the given condition is satisfied, means true, then it returns the specific value from the table. You will have to use WHERE clause to filter the records and fetching only necessary records.

The WHERE clause not only is used in SELECT statement, but it is also used in UPDATE, DELETE statement, etc., which will be covered in subsequent chapters.

Syntax

Following is the basic syntax of SQLite SELECT statement with WHERE clause.SELECT column1, column2, columnN FROM table_name WHERE [condition]

Example

You can specify a condition using Comparision or Logical Operators such as

>, <, =, LIKE, NOT, etc. Consider COMPANY table with 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

Following is a simple examples showing the usage of SQLite Logical Operators. Following SELECT statement lists down all the records where AGE is greater than or equal to 25 AND salary is greater than or equal to 65000.00.

sqlite> SELECT * FROM COMPANY WHERE AGE >= 25 AND SALARY >= 65000; ID NAME AGE ADDRESS SALARY ---------- ---------- ---------- ---------- ---------- 4 Mark 25 Rich-Mond 65000.0 5 David 27 Texas 85000.0

Following SELECT statement lists down all the records where AGE is greater than or equal to 25 OR salary is greater than or equal to 65000.00.

sqlite> SELECT * FROM COMPANY WHERE AGE >= 25 OR SALARY >= 65000; ID NAME AGE ADDRESS SALARY ---------- ---------- ---------- ---------- ---------- 1 Paul 32 California 20000.0 2 Allen 25 Texas 15000.0 4 Mark 25 Rich-Mond 65000.0 5 David 27 Texas 85000.0

Following SELECT statement lists down all the records where AGE is not NULL, which means all the records because none of the record has AGE equal to NULL.

sqlite> SELECT * FROM COMPANY WHERE AGE IS NOT NULL; 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

Following SELECT statement lists down all the records where NAME starts with 'Ki', does not matter what comes after 'Ki'.
sqlite> SELECT * FROM COMPANY WHERE NAME LIKE 'Ki%'; ID NAME AGE ADDRESS SALARY ---------- ---------- ---------- ---------- ---------- 6 Kim 22 South-Hall 45000.0

Following SELECT statement lists down all the records where NAME starts with ‘Ki’, does not matter what comes after ‘Ki’.

sqlite> SELECT * FROM COMPANY WHERE NAME GLOB 'Ki*'; ID NAME AGE ADDRESS SALARY ---------- ---------- ---------- ---------- ---------- 6 Kim 22 South-Hall 45000.0

Following SELECT statement lists down all the records where AGE value is either 25 or 27.

sqlite> SELECT * FROM COMPANY WHERE AGE IN ( 25, 27 ); ID NAME AGE ADDRESS SALARY ---------- ---------- ---------- ---------- ---------- 2 Allen 25 Texas 15000.0 4 Mark 25 Rich-Mond 65000.0 5 David 27 Texas 85000.0

Following SELECT statement lists down all the records where AGE value is neither 25 nor 27.

sqlite> SELECT * FROM COMPANY WHERE AGE NOT IN ( 25, 27 ); ID NAME AGE ADDRESS SALARY ---------- ---------- ---------- ---------- ---------- 1 Paul 32 California 20000.0 3 Teddy 23 Norway 20000.0 6 Kim 22 South-Hall 45000.0 7 James 24 Houston 10000.0

Following SELECT statement lists down all the records where AGE value is in BETWEEN 25 AND 27.

sqlite> SELECT * FROM COMPANY WHERE AGE BETWEEN 25 AND 27; ID NAME AGE ADDRESS SALARY ---------- ---------- ---------- ---------- ---------- 2 Allen 25 Texas 15000.0 4 Mark 25 Rich-Mond 65000.0 5 David 27 Texas 85000.0

Following SELECT statement makes use of SQL sub-query, where sub-query finds all the records with AGE field having SALARY > 65000 and later WHERE clause is being used along with EXISTS operator to list down all the records where AGE from the outside query exists in the result returned by the sub-query −

sqlite> SELECT AGE FROM COMPANY WHERE EXISTS (SELECT AGE FROM COMPANY WHERE SALARY > 65000); AGE ---------- 32 25 23 25 27 22 24

Following SELECT statement makes use of SQL sub-query where sub-query finds all the records with AGE field having SALARY > 65000 and later WHERE clause is being used along with > operator to list down all the records where AGE from the outside query is greater than the age in the result returned by the sub-query.

sqlite> SELECT * FROM COMPANY WHERE AGE > (SELECT AGE FROM COMPANY WHERE SALARY > 65000); ID NAME AGE ADDRESS SALARY ---------- ---------- ---------- ---------- ---------- 1 Paul 32 California 20000.0