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SELECT UCASE("hello world");
OR
SELECT UPPER("hello world");
Output: HELLO WORLD
2. LCASE() / LOWER()
The LCASE() and LOWER() functions are used to convert a string to lowercase.
Example:
SELECT LCASE("HELLO WORLD");
OR
SELECT LOWER("HELLO WORLD");
Output: hello world
3. MID() / SUBSTRING() / SUBSTR()
The MID(), SUBSTRING(), and SUBSTR() functions are used to extract a substring of a string, given the
specified starting position and length of the substring.
Example:
We extract the substring "world" from the string "hello world", as shown below:
SELECT MID("hello world", 7, 5);
OR
SELECT SUBSTR("hello world", 7, 5);
OR
SELECT SUBSTRING("hello world", 7, 5);
Output: world
4. LENGTH()
The LENGTH() function returns the length of a string in terms of characters.
SELECT LENGTH("Hello");
Output: 5
5. LEFT()
The LEFT() function extracts a specified number of characters from the left side of a string.
Example:
SELECT LEFT("MySQL", 2);
Output: My
In the above example, the LEFT() function extracts the first 2 characters from the string.
"MySQL".
6. RIGHT()
The RIGHT() function extracts a specified number of characters from the right side of a string.
Example:
SELECT RIGHT("MySQL", 3);
Output: SQL
In the above example, the RIGHT() function extracts the last 3 characters from the string "MySQL".
7. INSTR()
The INSTR() function returns the position of the first occurrence of a substring within a string.
Database Query using SQL 159

