// SimpleArgFunc represents functions with simple expression
// arguments.
type SimpleArgFunc struct {
	FunctionName string `parser:" @(\"AVG\" | \"MAX\" | \"MIN\" | \"SUM\" |  \"COALESCE\" | \"NULLIF\" | \"TO_STRING\" | \"TO_TIMESTAMP\" | \"UTCNOW\" | \"CHAR_LENGTH\" | \"CHARACTER_LENGTH\" | \"LOWER\" | \"UPPER\") "`

	ArgsList []*Expression `parser:"\"(\" (@@ (\",\" @@)*)?\")\""`
}

// CountFunc represents the COUNT sql function

	// Date and time
	sqlFnDateAdd     FuncName = "DATE_ADD"
	sqlFnDateDiff    FuncName = "DATE_DIFF"
	sqlFnExtract     FuncName = "EXTRACT"
	sqlFnToString    FuncName = "TO_STRING"
	sqlFnToTimestamp FuncName = "TO_TIMESTAMP"
	sqlFnUTCNow      FuncName = "UTCNOW"

	// String
	sqlFnCharLength      FuncName = "CHAR_LENGTH"
	sqlFnCharacterLength FuncName = "CHARACTER_LENGTH"
	sqlFnLower           FuncName = "LOWER"