---
title: Predicates & Expressions
description: Use Expr methods, logical operators, null checks, and expression composition.
---

# Predicates & Expressions

Columns in query callbacks are `Expr<T>` values.

## Comparison methods

These methods return `Expr<boolean>`:

- `eq(value, dialect)`
- `gt(value, dialect)`
- `gte(value, dialect)`
- `lt(value, dialect)`
- `lte(value, dialect)`
- `like(value, dialect)`

```ts
db.from("users").where(({ users }) => users.email.like("%@example.com", db.dialect));
```

Each comparison accepts either a literal value or another `Expr<T>`.

## Logical and null helpers

- `exprA.and(exprB)`
- `exprA.or(exprB)`
- `expr.isNull()`
- `expr.isNotNull()`

```ts
db.from("users").where(({ users }) =>
	users.managerId.isNotNull().and(users.email.like("%@company.com", db.dialect)),
);
```

## Ordering expressions

- `expr.asc()`
- `expr.desc()`

`orderBy` accepts either an `OrderExpr` or a plain `Expr` (plain defaults to ascending).

```ts
db.from("users").orderBy(({ users }) => users.email.asc());
```

## Building expressions directly

- `db.expr<T>\`...\``: context-aware SQL expression template
- `sqlExpr<T>(sql, params?)`: construct an expression manually

```ts
db.from("users").where(({ users }) =>
	db.expr<boolean>`lower(${users.email}) = lower(${"Alice@example.com"})`,
);
```

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