getValue()

Factory method to create a query function to return a single value from a query. Useful if you want to query a single COUNT() result.

Method signature

getValue({ name?: string, columnName: string, columnType: ColumnDefinition, query: GenericQueryFunction})

• name - optional name for logging
• columnName - the column to return values from
• columnType - column returned from the query. See column concepts
• query - function which returns the query to be executed. See querying

Return value

An async query function. Invoking this function with the arguments required by query will execute the query and return the value from the column specified by columnName

Query results

• null if no rows were returned by the query
• A value of the type of the specified column