PostgreSQL Exam PGCES-02 Topic 1 Question 37 Discussion

Actual exam question for PostgreSQL's PGCES-02 exam

Question #: 37
Topic #: 1

[All PGCES-02 Questions]

The table "custom" is defined below. The "id" column and "introducer" column are of

INTEGER type, and the "email" column is of TEXT type.

id | email | introducer ----+-- ---------------+-----------2 |

aaa@example.com | 1 3 |

bbb@example.com | 2 4 |

ccc@example.com | 2

Three SQL statements were executed in the following order:

UPDATE custom SET email = '' FROM custom c WHERE

custom.introducer = c.id; UPDATE custom SET introducer = NULL

WHERE introducer NOT IN (SELECT id FROM custom); DELETE

FROM custom WHERE id = 2 OR introducer = 2; Select the number of rows in the "custom" table after the execution.

A0 rows

B1 row

C2 rows

D3 rows

E4 rows

Show Suggested Answer

Suggested Answer: A

by Alishia at Dec 27, 2022, 12:15 AM

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Chery

16 hours ago

Hmm, this is a tricky one. I'm going to go with E) 4 rows. The SQL statements don't seem to delete any rows, they just update the data. So the final table should still have the original 4 rows.

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D) 3 rows seems like the right answer to me. The first two statements don't actually delete any rows, they just update the email and introducer columns. The third statement only removes 2 rows, so there should be 3 rows left.

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Carry

11 days ago

I'm going with B) 1 row. The third statement deletes the row with id = 2 and all rows where the introducer is 2, which means there should only be 1 row left in the table.

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Leah

17 days ago

I think the correct answer is C) 2 rows. The first statement updates the email column to empty for all rows where the introducer matches the id. The second statement sets the introducer to NULL for all rows where the introducer is not in the id column. The third statement deletes the row with id = 2 and all rows where the introducer is 2. This leaves us with 2 rows in the table.

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Junita

18 days ago

But if you look at the SQL statements carefully, it seems like only 2 rows will remain after the execution.

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Isreal

19 days ago

I disagree, I believe the answer is D) 3 rows.

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Junita

22 days ago

I think the answer is C) 2 rows.

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PostgreSQL Exam PGCES-02 Topic 1 Question 37 Discussion

Contribute your Thoughts:

Chery

Robt

Carry

Leah

Junita

Isreal

Junita