# Using Multiple Condition Filters

Combine conditions in a WHERE clause with AND, OR and NOT, and use parentheses so they're checked the way you mean.

Apprentice · T-SQL · SQL · Updated November 3, 2026

## After this lesson you can

- Combine filters with AND, OR, NOT and parentheses

## Key takeaways

- `AND` keeps a row only if every condition is true; `OR` keeps it if at least one is.
- `NOT` turns a condition around, and reads naturally with the other filters: `NOT LIKE`, `NOT IN`, `NOT BETWEEN` and `IS NOT NULL`.
- `AND` is checked before `OR`, so mixing them without parentheses can return rows you didn't mean.
- Whenever `AND` and `OR` appear in the same `WHERE`, add parentheses to make your meaning clear.

A real question often has more than one part. *Expensive products we have plenty of. Customers in London or Madrid.* SQL joins conditions with `AND`, `OR` and `NOT`, just as C# uses `&&`, `||` and `!`.

## AND: every condition

With `AND`, a row is kept only if **all** its conditions are true:

```sql
SELECT ProductName, UnitPrice, UnitsInStock
FROM Products
WHERE UnitPrice > 40 AND UnitsInStock > 20;
```

| ProductName | UnitPrice | UnitsInStock |
|---|---|---|
| Mishi Kobe Niku | 97.00 | 29 |
| Carnarvon Tigers | 62.50 | 42 |
| Sir Rodney's Marmalade | 81.00 | 40 |
| Schoggi Schokolade | 43.90 | 49 |
| Rössle Sauerkraut | 45.60 | 26 |
| Raclette Courdavault | 55.00 | 79 |
| Vegie-spread | 43.90 | 24 |

## OR: at least one condition

With `OR`, a row is kept if **any** of its conditions is true:

```sql
SELECT CompanyName, City
FROM Customers
WHERE City = 'London' OR City = 'Madrid';
```

That returns 9 customers: 6 in London and 3 in Madrid. (`City IN ('London', 'Madrid')` says the same thing.)

## NOT: the opposite

`NOT` turns a condition around:

```sql
SELECT ProductName, UnitPrice
FROM Products
WHERE NOT CategoryId = 1;
```

It also reads naturally with the other filters: `NOT LIKE`, `NOT IN`, `NOT BETWEEN` and `IS NOT NULL`.

## AND and OR together: use parentheses

When a `WHERE` mixes `AND` and `OR`, `AND` is checked first, just as `*` comes before `+`. That can give a different answer from the one you meant. Suppose you want cheap drinks or sauces: products in category 1 (Beverages) or 2 (Condiments) that cost under $10:

```sql
SELECT ProductName, UnitPrice
FROM Products
WHERE (CategoryId = 1 OR CategoryId = 2) AND UnitPrice < 10;
```

| ProductName | UnitPrice |
|---|---|
| Guaraná Fantástica | 4.50 |
| Rhönbräu Klosterbier | 7.75 |

Without the parentheses, `CategoryId = 1 OR CategoryId = 2 AND UnitPrice < 10` means "every beverage, whatever its price, **or** a condiment under $10", and returns all 12 beverages.

When `AND` and `OR` appear in the same `WHERE`, always add parentheses, even when you think the order is already right. They make your meaning clear to the database and to the next person who reads the query.

## Check yourself

2 questions to try on the lesson page.

## So what

`AND` narrows, `OR` widens, and parentheses make sure the database reads your question exactly the way you asked it.

## Key terms

- [Logical Predicate](https://www.ask-codey.com/glossary/logical-predicate)

## Cheat sheets

- [Using Multiple Condition Filters](https://www.ask-codey.com/cheat-sheets/where-in-t-sql-using-multiple-condition-filters-cheat-sheet)

Source: https://www.ask-codey.com/lessons/where-in-t-sql-using-multiple-condition-filters