leetcode

7 Database Problems

8 files changed, 45 insertions(+), 0 deletions(-)

diff --git a/ Problems/0197.sql b/ Problems/0197.sql

@@ -0,0 +1,4 @@

SELECT W2.id

FROM Weather W1, Weather W2

WHERE DATEDIFF(W2.recordDate, W1.recordDate) = 1 AND

W1.temperature < W2.temperaturea

diff --git a/ Problems/0577.sql b/ Problems/0577.sql

@@ -0,0 +1,5 @@

SELECT name, bonus

FROM Employee E

LEFT JOIN Bonus B

ON E.empId = B.empId

WHERE bonus < 1000 OR bonus is NULL

diff --git a/ Problems/1068.sql b/ Problems/1068.sql

@@ -0,0 +1,3 @@

SELECT product_name, year, price

FROM Sales S, Product P

WHERE S.product_id = P.product_id

diff --git a/ Problems/1280.sql b/ Problems/1280.sql

@@ -0,0 +1,9 @@

SELECT S.student_id, S.student_name, C.subject_name, COUNT(E.student_id) AS attended_exams

FROM Students S

CROSS JOIN Subjects C

LEFT JOIN Examinations E

ON S.student_id = E.student_id AND

C.subject_name = E.subject_name

GROUP BY S.student_id, C.subject_name

ORDER BY S.student_id, C.subject_name

diff --git a/ Problems/1378.sql b/ Problems/1378.sql

@@ -0,0 +1,4 @@

SELECT unique_id, name

FROM Employees E

LEFT JOIN EmployeeUNI U

ON E.id = U.id

diff --git a/ Problems/1581.sql b/ Problems/1581.sql

@@ -0,0 +1,6 @@

SELECT V.customer_id, COUNT(V.visit_id) AS count_no_trans

FROM Visits V

LEFT JOIN Transactions T

ON V.visit_id = T.visit_id

WHERE T.amount IS NULL

GROUP BY V.customer_id

diff --git a/ Problems/1661.sql b/ Problems/1661.sql

@@ -0,0 +1,7 @@

SELECT A1.machine_id, ROUND(AVG(A2.timestamp - A1.timestamp), 3) AS processing_time

FROM Activity A1, Activity A2

WHERE A1.machine_id = A2.machine_id AND

A1.process_id = A2.process_id AND

A1.activity_type = 'start' AND

A2.activity_type = 'end'

GROUP BY A1.machine_id

diff --git a/ README.md b/ README.md

@@ -187,6 +187,7 @@ for solving problems. | 0193 | Easy | [Valid Phone Numbers](Problems/0193.sh) | | 0194 | Medium | [Transpose File](Problems/0194.sh) | | 0195 | Easy | [Tenth Line](Problems/0195.sh) |

| 0197 | Easy | [Rising Temperature](Problems/0197.cpp) |

| 0198 | Medium | [House Robber](Problems/0198.cpp) | | 0199 | Medium | [Binary Tree Right Side View](Problems/0199.cpp) | | 0200 | Medium | [Number of Islands](Problems/0200.cpp) |

@@ -351,6 +352,7 @@ for solving problems. | 0566 | Easy | [Reshape the Matrix](Problems/0566.cpp) | | 0567 | Medium | [Permutation in String](Problems/0567.cpp) | | 0572 | Easy | [Subtree of Another Tree](Problems/0572.cpp) |

| 0577 | Easy | [Employee Bonus](Problems/0577.cpp) |

| 0583 | Medium | [Delete Operation for Two Strings](Problems/0583.cpp) | | 0584 | Easy | [Find Customer Referee](Problems/0584.cpp) | | 0589 | Easy | [N-ary Tree Preorder Traversal](Problems/0589.cpp) |

@@ -526,6 +528,7 @@ for solving problems. | 1048 | Medium | [Longest String Chain](Problems/1048.cpp) | | 1051 | Easy | [Height Checker](Problems/1051.cpp) | | 1061 | Medium | [Lexicographically Smallest Equivalent String](Problems/1061.cpp) |

| 1068 | Easy | [Product Sales Analysis I](Problems/1068.cpp) |

| 1071 | Easy | [Greatest Common Divisor of Strings](Problems/1071.cpp) | | 1072 | Medium | [Flip Columns For Maximum Number of Equal Rows](Problems/1072.cpp) | | 1079 | Medium | [Letter Tile Possibilities](Problems/1079.cpp) |

@@ -578,6 +581,7 @@ for solving problems. | 1268 | Medium | [Search Suggestions System](Problems/1268.cpp) | | 1269 | Hard | [Number of Ways to Stay in the Same Place After Some Steps](Problems/1269.cpp) | | 1277 | Medium | [Count Square Submatrices with All Ones](Problems/1277.cpp) |

| 1280 | Easy | [Students and Examinations](Problems/1280.cpp) |

| 1282 | Medium | [Group the People Given the Group Size They Belong To](Problems/1282.cpp) | | 1286 | Medium | [Iterator for Combination](Problems/1286.cpp) | | 1290 | Easy | [Convert Binary Number in a Linked List to Integer](Problems/1290.cpp) |

@@ -621,6 +625,7 @@ for solving problems. | 1373 | Hard | [Maximum Sum BST in Binary Tree](Problems/1373.cpp) | | 1375 | Medium | [Number of Times Binary String Is Prefix-Aligned](Problems/1375.cpp) | | 1376 | Medium | [Time Needed to Inform All Employees](Problems/1376.cpp) |

| 1378 | Easy | [Replace Employee ID With The Unique Identifier](Problems/1378.cpp) |

| 1379 | Easy | [Find a Corresponding Node of a Binary Tree in a Clone of That Tree](Problems/1379.cpp) | | 1381 | Medium | [Design a Stack With Increment Operation](Problems/1381.cpp) | | 1382 | Medium | [Balance a Binary Search Tree](Problems/1382.cpp) |

@@ -689,6 +694,7 @@ for solving problems. | 1575 | Medium | [Count All Possible Routes](Problems/1575.cpp) | | 1578 | Medium | [Minimum Time to Make Rope Colorful](Problems/1578.cpp) | | 1579 | Hard | [Remove Max Number of Edges to Keep Graph Fully Traversable](Problems/1579.cpp) |

| 1581 | Easy | [Customer Who Visited but Did Not Make Any Transactions](Problems/1581.cpp) |

| 1583 | Medium | [Count Unhappy Friends](Problems/1583.cpp) | | 1584 | Medium | [Min Cost to Connect All Points](Problems/1584.cpp) | | 1600 | Medium | [Throne Inheritance](Problems/1600.cpp) |

@@ -711,6 +717,7 @@ for solving problems. | 1653 | Medium | [Minimum Deletions to Make String Balanced](Problems/1653.cpp) | | 1657 | Medium | [Determine if Two Strings Are Close](Problems/1657.cpp) | | 1658 | Medium | [Minimum Operations to Reduce X to Zero](Problems/1658.cpp) |

| 1661 | Easy | [Average Time of Process per Machine](Problems/1661.cpp) |

| 1662 | Easy | [Check If Two String Arrays are Equivalent](Problems/1662.cpp) | | 1663 | Medium | [Smallest String With A Given Numeric Value](Problems/1663.cpp) | | 1664 | Medium | [Ways to Make a Fair Array](Problems/1664.cpp) |