func TestNewRequestID(t *testing.T) {
	// Ensure that it returns an alphanumeric result of length 16.
	id := mustGetRequestID(UTCNow())

	if len(id) != 16 {
		t.Fail()
	}

	var e rune
	for _, char := range id {
		e = char

		// Ensure that it is alphanumeric, in this case, between 0-9 and A-Z.
		if !(('0' <= e && e <= '9') || ('A' <= e && e <= 'Z')) {
			t.Fail()
		}
	}

// 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
type CountFunc struct {

	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"
	sqlFnSubstring       FuncName = "SUBSTRING"
	sqlFnTrim            FuncName = "TRIM"
	sqlFnUpper           FuncName = "UPPER"

)

const (
	mysqlTableExists = `SELECT 1 FROM %s;`
	// Some MySQL has a 3072 byte limit on key sizes.
	mysqlCreateNamespaceTable = `CREATE TABLE %s (
             key_name VARCHAR(3072) NOT NULL,
             key_hash CHAR(64) GENERATED ALWAYS AS (SHA2(key_name, 256)) STORED NOT NULL PRIMARY KEY,
             value JSON)
           CHARACTER SET = utf8mb4 COLLATE = utf8mb4_bin ROW_FORMAT = Dynamic;`