Tag: databases

The two statements produce identical results.

The second statement returns a syntax error

There is no need to specify DESC because the results are sorted in descending order by default

The two statements can be made to produce identical results by adding a column alias for the salary column in the second SQL statement.

SELECT TO_DATE(SYSDATE, 'FMDAY, DD Month, YYYY') FROM dual;

SELECT TO_CHAR(SYSDATE, 'FMDD, DY Month, 'YYYY') FROM dual;

SELECT TO_CHAR(SYSDATE, 'FMDay, DD Month, YYYY') FROM dual;

SELECT TO_CHAR(SYSDATE, 'FMDY, DDD Month, YYYY') FROM dual;

SELECT TO_DATE(SYSDATE, 'FMDY, DDD Month, YYYY') FROM dual;

SELECT SUBSTR ('Hello',) FROM dual;

SELECT INITCAP (TRIM ('Hello World',1,1) FROM dual;

SELECT LOWER (SUBSTR ('Hello World',1,1) FROM dual

SELECT LOWER (SUBSTR ('Hello World',2,1) FROM dual;

SELECT LOWER (TRIM ('H' FROM 'Hello World')) FROM dual;

Updating

Viewing

Deleting

Inserting

Truncating

INSTR returns the numeric position of a named character.

NVL2 returns the first non-null expression in the expression list.

DECODE translates an expression after comparing it to each search value

TRIM trims the heading of trailing characters (or both) from a character string

NVL compares two expressions and returns null if they are equal, or the first expression of they are not equal

NULLIF compares twp expressions and returns null if they are equal, or the first expression if they are not equal

Convert 10 to 'TEN'

Convert '10' to 10

Convert '10' to '10'

Convert 'TEN' to 10

Convert a date to a character expression

Convert a character expression to a date

The sort is in ascending by order by default

The sort is in descending order by default

The ORDER BY clause must precede the WHERE clause

The ORDER BY clause is executed on the client side

The ORDER BY clause comes last in the SELECT statement

The ORDER BY clause is executed first in the query execution

update more than one row at a time.

delete more than one row at a time.

update only one row at a time.

delete only one row at a time.

COMMIT

MERGE

UPDATE

DELETE

CREATE

DROP

FROM

SEARCH

WHERE

while