Perguntas Duvida no select SQL

SELECT F1_FILIAL, F1_DOC, F1_SERIE, F1_FORNECE, A1_COD AS COD, F1_LOJA, A1_LOJA AS LOJA, A1_NOME AS NOME, F1_EMISSAO, F1_DTDIGIT, F1_ESPECIE, F1_TIPO, F1_FORMUL, F1_USUARIO, F1_CHVNFE, F1_USITNFE, F1_UNFECON
FROM SF1010, SA1010
WHERE F1_FILIAL = '02'
AND F1_DTDIGIT >= '20140623' AND F1_DTDIGIT <= '20140625'
AND F1_FORMUL <> 'S'
AND F1_ESPECIE IN ('SPED','CTE')
AND F1_TIPO IN ('B','D')
AND F1_FORNECE = A1_COD
AND F1_LOJA = A1_LOJA
AND SF1010.D_E_L_E_T_ = ''
AND SA1010.D_E_L_E_T_ = ''
ORDER BY F1_DOC

UNION ALL

SELECT F1_FILIAL, F1_DOC, F1_SERIE, F1_FORNECE, A2_COD AS COD, F1_LOJA, A2_LOJA AS LOJA, A2_NOME AS NOME, F1_EMISSAO, F1_DTDIGIT, F1_ESPECIE, F1_TIPO, F1_FORMUL, F1_USUARIO, F1_CHVNFE, F1_USITNFE, F1_UNFECON
FROM SF1010, SA2010
WHERE F1_FILIAL = '02'
AND F1_DTDIGIT >= '20140623' AND F1_DTDIGIT <= '20140625'
AND F1_FORMUL <> 'S'
AND F1_ESPECIE IN ('SPED','CTE')
AND F1_TIPO NOT IN ('B','D')
AND F1_FORNECE = A2_COD
AND F1_LOJA = A2_LOJA
AND SF1010.D_E_L_E_T_ = ''
AND SA2010.D_E_L_E_T_ = ''
ORDER BY F1_DOC