SELECT <column_names>

FROM <table_name>

WHERE NOT NULL (<column_name>);

SELECT <column_names>

FROM <table_name>

WHERE <column_name>= NULL;

SELECT <column_names>

FROM <table_name>

WHERE <column_name> <> 0 AND <column_name> <> '';

SELECT <column_names>

FROM <table_name>

WHERE NULL (<column_name>) = 1;

SELECT <column_names>

FROM <table_name>

WHERE <column_name> IS NULL;

SELECT F.NOME, F2.NOME

FROM FUNCIONARIO F, FUNCIONARIO F2

WHERE F.ID_FUNCIONARIO_SUPERIOR = F2.ID

SELECT NOME, F2.NOME

FROM FUNCIONARIO, FUNCIONARIO F2

WHERE ID = F2.ID_FUNCIONARIO_SUPERIOR

SELECT FUNC.NOME, SUP.NOME

FROM FUNCIONARIO FUNC, FUNCIONARIO SUP

WHERE FUNC.ID = SUP.ID

SELECT F1.NOME, F2.NOME

FROM FUNCIONARIO F1, F2

WHERE F.ID_FUNCIONARIO_SUPERIOR IS F2.ID

SELECT NOME NOME_FUNC, NOME NOME_SUP

FROM FUNCIONARIO

WHERE ID = ID_FUNCIONARIO_SUPERIOR