This function is an implementation detail of the query interface. Do not use it directly.

See https://github.com/groue/GRDB.swift/#the-query-interface

Low Level Query Interface

Returns an SQL string that represents the collection.

When the arguments parameter is nil, any value must be written down as a literal in the returned SQL:

var arguments: StatementArguments? = nil
let collection = SQLExpressionsArray([1,2,3])
collection.collectionSQL(&arguments)  // "1,2,3"

When the arguments parameter is not nil, then values may be replaced by ? or colon-prefixed tokens, and fed into arguments.

var arguments = StatementArguments()
let collection = SQLExpressionsArray([1,2,3])
collection.collectionSQL(&arguments)  // "?,?,?"
arguments                             // [1,2,3]

Returns an expression that check whether the collection contains the expression.

The default implementation returns a SQLExpressionContains which applies the IN operator:

let request = Person.select(Column("id"))
request.contains(Column("id"))   // id IN (SELECT id FROM persons)