不同的數據庫表，求總條數

SELECT
	count(*) AS total from (
		SELECT
			products.Validator,
			policies.ProductID,
			policies.PlanID,
			policies.DateGen,
			policies.PHName,
			policies.ProductName,
			policies.PolicyNumber,
			policies.DateStart,
			policies.CorpName,
			policies.CorpID,
			policies.TotalPremium,
			policies.DateEnd,
			policies.PolicyState,
			policies.ID
		FROM
			policies
		LEFT JOIN products ON products.ProductID = policies.ProductID
		WHERE
			policies.CorpID IN (
				16899,
				16900,
				16902,
				16915,
				16918,
				16949
			)
		AND PolicyNumber != ''
		AND DateIssue >= '2004-05-01'
		AND DateIssue <= '2019-05-21'
		UNION ALL
			SELECT
				products.Validator,
				policies.ProductID,
				policies.PlanID,
				policies.DateGen,
				policies.PHName,
				policies.ProductName,
				policies.PolicyNumber,
				policies.DateStart,
				policies.CorpName,
				policies.CorpID,
				policies.TotalPremium,
				policies.DateEnd,
				policies.PolicyState,
				policies.ID
			FROM
				policies
			LEFT JOIN products ON products.ProductID = policies.ProductID
			LEFT JOIN policy_correct ON policy_correct.PolicyID = policies.ID
			WHERE
				policies.CorpID IN (
					16899,
					16900,
					16902,
					16915,
					16918,
					16949
				)
			AND policies.PolicyNumber != ''
			AND policy_correct.CreateTime >= '2004-05-01'
			AND .policy_correct.CreateTime <= '2019-05-21'
	)as temp;