Read scalar values

Use scalar methods when you need the first column of the first result row. The examples assume database is a configured DatabaseUrl; see your first query for setup.

Read a value

var count = await database.ReadScalarAsync(
    "SELECT COUNT(*) FROM Customer");

For a typed result, choose the CLR type returned by your provider. The nullable ReadScalar<T> overload casts the provider result; it does not convert every SQL value to an arbitrary CLR type. For example, SQL COUNT(*) may be a 32-bit or 64-bit integer depending on the provider.

Handle SQL NULL

Choose a nullable or reference type when SQL NULL is expected:

var oldest = await database.ReadScalarAsync<DateTime?>(
    "SELECT MIN(BirthDate) FROM Customer");

Use ReadScalarNonNull or its asynchronous equivalent when a value is required. A missing or SQL NULL result throws InvalidOperationException.

Reuse a query

Scalar methods accept SQL strings, rendered command providers, and templates with values. See Use SQL templates for a complete template example and the distinction between rendered literals and bound parameters.