Questec Consulting Senior Application Support Engineer Interview Questions and Answers

Primary keys uniquely identify records in a table, while foreign keys establish relationships between tables.

• Primary keys ensure data integrity by enforcing uniqueness and preventing duplicate records.

• Foreign keys create relationships between tables, allowing data to be linked and referenced across multiple tables.

• Primary keys are typically used as foreign keys in related tables to establish relationships.

• Foreign keys ...read more

Inner joins are used to combine rows from two or more tables based on a related column between them.

• Inner joins return only the matching rows from both tables.

• The join condition is specified using the ON keyword followed by the column(s) to join on.

• Inner joins can be used to retrieve data from multiple tables based on a common column.

• Example: SELECT * FROM table1 INNER JOIN table2 ON table1.column = table2.column;

The SELECT command is used to retrieve data from a database table.

• SELECT is a fundamental SQL command used in database management systems.

• It allows you to specify the columns and rows you want to retrieve from a table.

• You can use various clauses like WHERE, ORDER BY, GROUP BY, etc. to filter and sort the data.

• The result of a SELECT query is a result set or a cursor containing the selected data.

• Example: SELECT * FROM em...read more

To create a table, use the CREATE TABLE statement in SQL.

• Specify the table name after the CREATE TABLE keyword.

• List the column names and their data types within parentheses.

• Add any constraints or indexes as needed.

• Example: CREATE TABLE employees (id INT, name VARCHAR(50), age INT);