How can we find the number of rows in a table using MySQL?
Use this for MySQL
SELECT COUNT(*) FROM table_name;
What’s the difference between md5(), crc32() and sha1() crypto on PHP?
The major difference is the length of the hash generated. CRC32 is, evidently, 32 bits, while sha1() returns a 128 bit value, and md5() returns a 160 bit value. This is important when avoiding collisions.
How can we find the number of rows in a result set using PHP?
Here is how can you find the number of rows in a result set in PHP:
$result = mysql_query($any_valid_sql, $database_link);
$num_rows = mysql_num_rows($result);
echo “$num_rows rows found”;
How many ways we can we find the current date using MySQL?
SELECT CURDATE();
SELECT CURRENT_DATE();
SELECT CURTIME();
SELECT CURRENT_TIME();
Give the syntax of GRANT commands?
The generic syntax for GRANT is as following
GRANT [rights] on [database] TO [username@hostname] IDENTIFIED BY [password]
Now rights can be:
a) ALL privilages
b) Combination of CREATE, DROP, SELECT, INSERT, UPDATE and DELETE etc.
We can grant rights on all databse by usingh *.* or some specific database by database.* or a specific table by database.table_name.
Give the syntax of REVOKE commands?
The generic syntax for revoke is as following
REVOKE [rights] on [database] FROM [username@hostname]
Now rights can be:
a) ALL privilages
b) Combination of CREATE, DROP, SELECT, INSERT, UPDATE and DELETE etc.
We can grant rights on all databse by usingh *.* or some specific database by database.* or a specific table by database.table_name.
Answer the questions with the following assumption
The structure of table view buyers is as follows:
+-------------+-------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------------+-------------+------+-----+---------+----------------+
| user_pri_id | int(15) | | PRI | NULL | auto_increment |
| userid | varchar(10) | YES | | NULL | |
+-------------+-------------+------+-----+---------+----------------+
The value of user_pri_id of the last row is 2345. What will happen in the following conditions?
Condition 1: Delete all the rows and insert another row. What is the starting value for this auto incremented field user_pri_id?
Condition 2: Delete the last row (having the field value 2345) and insert another row. What is the value for this auto incremented field user_pri_id?
In both conditions, the value of this auto incremented field user_pri_id is 2346.
