SQL Questions

LIKE is a keyword that is used in the WHERE clause. Basically, LIKE allows us to do a search based operation on a pattern rather than specifying exactly what is desired (as in IN) or spell out a range (as in BETWEEN).

The syntax is as follows:
SELECT "column_name"
FROM "table_name"
WHERE "column_name" LIKE {PATTERN}

{PATTERN} often consists of wildcards.

In SQL, there are two wildcards:


% (percent sign) represents zero, one, or more characters.

_ (underscore) represents exactly one character.

More :: Certification Questions on SQL

The built in function called GetDate() returns the time stamp.

SELECT COUNT(*), sex from Employees  WHERE  DOB BETWEEN ‘01/01/1960 ' AND ‘31/12/1975’  GROUP BY sex;

SQL has IsDate() function which is used to check passed value is date or not of specified format ,it returns 1(true) or 0(false) accordingly.

SELECT  ISDATE('1/08/13') AS "MM/DD/YY";

It will return 0 because passed date is not in correct format.

SELECT  * from Employees  WHERE  upper(EmpName) like upper('joe%');

The Data Definition Language (DDL) is used to manage table and index structure.

CREATE,

ALTER,

RENAME,

DROP and

TRUNCATE

statements are the names of few data definition elements.

In SQL, a SQL view is a virtual table based on the result-set of an SQL statement. A view contains rows and columns, just like a real table.

SQL views can be used to hide rows and columns and complicated SQL syntax.

The fields in a view are fields from one or more real tables in the database.