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+# WHERE Clause
+
+The `WHERE` clause filters query results. It restricts the rows returned based on specified conditions. Position this clause directly after  `FROM`.
+
+```sql
+SELECT column_name FROM table_name WHERE condition;
+```
+
+The `condition` is an expression evaluating to true, false, or unknown. Only rows where the condition evaluates to true are included in the result set.
+
+## WHERE Clause Example
+
+Consider a `users` table. To retrieve only active users:
+
+```sql
+SELECT DISTINCT username, email, active FROM users WHERE active=true;
+```
+
+Output demonstrates results filtered by the `active= true` condition.
+
+| username | email             | active |
+|----------|-------------------|--------|
+| shinobi  | b@javateamsix.com |      1 |
+| tony     | t@javateamsix.com |      1 |
+
+Conversely, retrieve inactive users by setting `active=false`:
+
+```sql
+SELECT DISTINCT username, email, active FROM users WHERE active=false;
+```
+
+Output reflects rows where `active ` is false (0).
+
+| username    | email             | active |
+|-------------|-------------------|--------|
+| Java Team Six | d@javateamsix.com |      0 |
+
+To select users with a specific username, like  'shinobi':
+
+```sql
+SELECT username, email, active FROM users WHERE username='shinobi';
+```
+
+Multiple entries match the username 'shinobi'.
+
+| username | email             | active |
+|----------|-------------------|--------|
+| shinobi  | b@javateamsix.com |      1 |
+| shinobi  | b@javateamsix.com |      1 |
+
+## Operators
+
+Comparison operators define conditions within the `WHERE` clause.
+
+*   `= ` : Equal to
+*   `!=` : Not equal to
+*   `>` : Greater than
+*   `>=` : Greater than or equal to
+*   `<` : Less than
+*   `<=` : Less than  or equal to
+
+## AND Keyword
+
+Combine multiple conditions with the `AND` keyword. The `AND` operator returns rows where *all* conditions are true.
+
+Example: Select active users with username 'shinobi'.
+
+```sql
+SELECT  * FROM users WHERE username='shinobi' AND active=true;
+```
+
+Output shows rows matching both the username and active status.
+
+| id | username | about | birthday | active | email             |
+|----|---------- |-------|----------|--------|-------------------|
+|  2 | shinobi  | NULL  | NULL     |      1 | b@javateamsix.com |
+|  5 | shinobi  | NULL  | NULL      |      1 | b@javateamsix.com |
+
+If no rows satisfy *all* conditions, the result is empty.
+
+```sql
+SELECT * FROM users WHERE username='shinobi' AND active=false;
+```
+
+-- Output:
+Empty set.
+
+## OR Keyword
+
+Combine conditions with the `OR` keyword. The `OR` operator returns rows where *any* condition is true. Use `OR` to fetch data matching one criterion or another.
+
+Example:  Select users with username 'shinobi' OR where active is false.
+
+```sql
+SELECT * FROM users WHERE username='shinobi' OR active=false;
+```
+
+Output includes rows where either condition is met.
+
+| id  | username    | about | birthday | active | email             |
+|----|-------------|-------|----------|--------|-------------------|
+|  2 | shinobi     | NULL  | NULL     |      1 | b@javate amsix.com |
+|  3 | Java Team Six | NULL  | NULL     |      0 | d@javateamsix.com |
+|  5 | shinobi     | NULL  | NULL     |      1  | b@javateamsix.com |
+|  6 | Java Team Six | NULL  | NULL     |      0 | d@javateamsix.com |
+
+## LIKE Operator
+
+The `LIKE` operator performs  pattern matching. It is typically used with wildcard characters (`%` for any sequence of characters, `_` for any single character).
+
+Example: Select users where the username contains the letter 'y'.
+
+```sql
+SELECT * FROM users  WHERE username LIKE '%y%';
+```
+
+Output includes usernames containing 'y'.
+
+| id | username | about | birthday | active | email             |
+|----|----------|-------|----------|--------|-------------------|
+|   2 | shinobi  | NULL  | NULL     |      1 | b@javateamsix.com |
+|  4 | tony     | NULL  | NULL     |      1 | t@javateamsix.com  |
+
+## IN Operator
+
+The `IN` operator checks if a column's value matches any value in a specified list. This simplifies conditions that would otherwise require multiple `OR` statements.
+
+Example: Select users with username 'shinobi' or ' Java Team Six'.
+
+```sql
+SELECT * FROM users WHERE username IN ('shinobi', 'Java Team Six');
+```
+
+Output shows all rows where the username is in the provided list.
+
+| id | username    | about | birthday  | active | email             |
+|----|-------------|-------|----------|--------|-------------------|
+|  2 | shinobi     | NULL  | NULL     |      1 | b@javateamsix.com |
+|   3 | Java Team Six | NULL  | NULL     |      0 | d@javateamsix.com |
+|  5 | shinobi     | NULL  | NULL     |      1 | b@javateamsix .com |
+|  6 | Java Team Six | NULL  | NULL     |      0 | d@javateamsix.com |
+
+## IS Operator
+
+Use the `IS` operator specifically for checking `NULL` values . The `=` operator cannot be used for this purpose.
+
+To find rows where `about` is `NULL`:
+
+```sql
+SELECT * FROM users WHERE about IS NULL;
+```
+
+To find rows where `about` is not  `NULL`:
+
+```sql
+SELECT * FROM users WHERE about IS NOT NULL;
+```
+
+## BETWEEN Operator
+
+The `BETWEEN` operator selects values within a defined range. This range is inclusive of the start and end values.  Applicable to numbers, text, and dates.
+
+Example: Select users with an ID between 3 and 6 (inclusive).
+
+```sql
+SELECT * FROM users WHERE id BETWEEN 3 AND 6;
+```
+
+Output displays rows where  `id` is within the specified range.
+
+| id | username    | about | birthday | active | email             |
+|----|-------------|-------|----------|--------|-------------------|
+|  3 | Java Team Six | NULL   | NULL     |      0 | d@javateamsix.com |
+|  5 | shinobi     | NULL  | NULL     |      1 | b@javateamsix.com |
+|  6 |  Java Team Six | NULL  | NULL     |      0 | d@javateamsix.com |
+
+## Summary
+
+The `WHERE` clause and its associated operators are fundamental tools for precisely selecting data subsets, essential for efficient database interaction  from Java applications.