1z0-071 Exam Dumps - Oracle Database 12c SQL

Based on the table structure given in the image, to return the value 'CUBE' from the 'bricks' table when joined with 'boxes', the condition must ensure that the weight of the bricks is within the allowed weight range specified in the 'boxes' table for a 'SMALL' box size.

A. True. Since MAX_WEIGHT is 0, a comparison using >= min_weight AND weight < max_weight will only return rows where the weight is less than 0, which is impossible for actual weight values, suggesting there might be a mistake in the data provided or the comparison logic.

E. True. NOT (weight > max_weight) effectively translates to 'where weight is less than or equal to max_weight'. However, since MAX_WEIGHT is 0, this condition would only be true if the weight is not greater than 0, which can only happen if the weight is 0 or less. This seems to indicate an anomaly where either the data is incorrect, or the condition is meant to handle a case where the weight is zero or possibly a negative placeholder value.

Both B and D will potentially return more than just 'CUBE' if there are bricks with weights greater than MIN_WEIGHT. C is incorrect because BETWEEN is inclusive, and there are no weights that are both greater than or equal to MIN_WEIGHT and less than or equal to MAX_WEIGHT when MAX_WEIGHT is 0.

A. This statement is incorrect. An INVISIBLE index is maintained during DML operations just like a VISIBLE index. The difference is that an INVISIBLE index is not used by the optimizer unless explicitly hinted. B. This statement is correct. When creating a table, you can define indexes on one or more columns as part of the table definition. C. This statement is incorrect. While a DROP INDEX statement will drop the index, it does not always prevent updates to the table. If the index is marked as unusable or is an invisible index, for example, updates can still be performed. D. This statement is correct. It is possible to have both a UNIQUE index and a non-unique index on the same column. The UNIQUE index enforces the uniqueness of column values, while the non-unique index does not. E. This statement is correct to some extent. Descending indexes are not function-based indexes per se, but they are indexes on which the data is sorted in descending order, as opposed to the default ascending order. However, descending indexes are conceptually related to function-based indexes because they alter the way the indexed data is stored. F. This statement is incorrect. The use of an index in query execution depends on the optimizer's decision, which is based on statistics and the cost associated with using the index. There are situations where the optimizer may choose a full table scan even if there is an index on the filter column.

References can be found in the Oracle Database Concepts Guide and the SQL Language Reference documentation, which detail the behavior of indexes and how they are managed within the Oracle database.

The statement true regarding the CREATE TABLE command:

C. The NEW_SALES table would not get created because the column names in the CREATE TABLE command and the SELECT clause do not match: The SQL command tries to create a table with columns prod_id, cust_id, and order_date, but the SELECT statement specifies columns prod_id, cust_id, and time_id. The mismatch in column names and the number of columns specified will prevent the table from being created.

Incorrect options:

A: It is possible to specify a DEFAULT value in the column definition when creating a table with the CREATE TABLE AS SELECT syntax.

B: Not all NOT NULL constraints (or any other constraints, for that matter) are automatically passed to the new table unless explicitly stated in the CREATE TABLE statement.

D: FOREIGN KEY constraints are not automatically included when creating a table using the CREATE TABLE AS SELECT syntax; they would need to be added explicitly afterwards.

The LISTAGG function is used in Oracle to aggregate strings from data in a group specified by the GROUP BY clause, producing a single row of concatenated values. The correct syntax also specifies an ORDER BY clause within the WITHIN GROUP parenthesis to sort the values in the concatenated list.

The correct query is:

SELECT deptno, LISTAGG(ename, ', ') WITHIN GROUP (ORDER BY ename) AS employee_list FROM emp GROUP BY deptno;

This statement will return a comma-separated list of employee names (ename) in alphabetical order for each department (deptno) in the EMP table.

B: True. The MAX and MIN functions can be applied to columns with character data types. These functions will return the highest or lowest values in a set of rows, based on alphabetical order for character data. This allows these aggregate functions to be versatile and useful across different data types, including numerical, date, and character types.

A. True, when using the ORDER BY clause with set operators like UNION, you can refer to the results by column positions. This allows for consistent sorting behavior across potentially heterogeneous SELECT statements.D. True, only the column names or positions from the first SELECT statement are recognized in the ORDER BY clause when used with set operators like UNION, as the result set is treated as if it originated from the first SELECT structure.

References:

Oracle documentation on ORDER BY with set operators: Oracle Database SQL Language Reference

Explanation of ORDER BY usage: Oracle SQL Tips

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When writing SQL statements with multiple conditions in the WHERE clause, it's important to understand how logical operators like AND and OR work. These operators are used to filter records based on more than one condition:

The AND operator displays a record if all the conditions separated by AND are TRUE.

The OR operator displays a record if any of the conditions separated by OR is TRUE.

The precedence of these operators is also important: AND operations are always evaluated before OR operations unless parentheses are used to explicitly define the order of operations. Therefore, conditions enclosed in parentheses are evaluated first as per the standard SQL operator precedence.

Given this understanding, let's evaluate the options:

Option A uses parentheses to group the borrowed_date and transaction_type conditions together, ensuring these are evaluated first before the OR operator. This means the query will return records that meet both of these conditions or records with member_id 'A101' or 'A102', regardless of other conditions.

Option D does not use parentheses around the borrowed_date and transaction_type conditions but does use them to group the member_id conditions. Since the AND operator has higher precedence than the OR, this query will first evaluate the borrowed_date and transaction_type conditions, then evaluate the grouped member_id conditions. The outcome is records that have a borrowed_date of SYSDATE, a transaction_type of 'RM', and a member_id of either 'A101' or 'A102'.

The results of Options A and D are effectively the same, even though the use of parentheses is different. This is because in both cases, the evaluation of the borrowed_date and transaction_type conditions will be performed first due to their grouping by parentheses in Option A and the precedence of AND over OR in Option D. Therefore, they will both return all records where borrowed_date equals SYSDATE and transaction_type equals 'RM', plus any records where member_id is either 'A101' or 'A102'.

For further details on SQL operator precedence and logical operators, you can refer to Oracle Database SQL Language Reference 12c documentation, specifically the sections on conditional expressions.

To find customers whose last names start with "Mc" or "MC", we need to ensure our SQL query correctly identifies and compares these prefixes regardless of case variations. Let's analyze the given options:

Option B: WHERE UPPER(SUBSTR(cust_name, INSTR(cust_name, ' ') + 1)) LIKE UPPER('MC%')This clause uses UPPER to convert both the extracted substring (starting just after the first space, assuming it indicates the start of the last name) and the comparison string 'MC%' to uppercase. This ensures case-insensitive comparison. The LIKE operator is used to match any last names starting with "MC", which will correctly capture both "Mc" and "MC". This option is correct.

Option C: WHERE INITCAP(SUBSTR(cust_name, INSTR(cust_name, ' ') + 1)) LIKE 'Mc%'This clause applies INITCAP to the substring, which capitalizes the first letter of each word and makes other letters lowercase. The result is compared to 'Mc%', assuming only the last name follows the space. This approach will match last names starting with "Mc" (like "McEwen"), but not "MC". However, considering we're looking for "Mc" specifically, this clause works under the assumption that "Mc" is treated as proper capitalization for these last names. Thus, it can also be considered correct, albeit less inclusive than option B.

The other options either use incorrect syntax or apply case-sensitive matches without ensuring that both "Mc" and "MC" are captured:

Option A: Contains syntax errors (unmatched quotes and wrong use of IN).

Option D: Uses case-sensitive match without combining both "Mc" and "MC".

Option E: Only matches "Mc", which is too specific.