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“SQL Interview Questions and Answers will guide us now that SQL (Structured Query Language) is a database computer language designed for managing data in relational database management systems (RDBMS), and originally based upon Relational Algebra. So learn SQL or get preparation for the job of SQL (Structured Query Language) with the help of this SQL Interview Questions with Answers guide”



172 SQL Questions And Answers

1⟩ What is sql BREAK?

BREAK command clarify reports by suppressing repeated values, skipping lines & allowing for controlled break points.

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2⟩ What is SET?

SET command changes the system variables affecting the report environment.

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4⟩ What is a Character Functions?

Character Functions are INITCAP, UPPER, LOWER, SUBSTR & LENGTH. Additional functions are GREATEST & LEAST. Group Functions returns results based upon groups of rows rather than one result per row, use group functions. They are AVG, COUNT, MAX, MIN & SUM.

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5⟩ What is NVL?

NVL : Null value function converts a null value to a non-null value for the purpose of evaluating an expression. Numeric Functions accept numeric I/P & return numeric values. They are MOD, SQRT, ROUND, TRUNC & POWER.

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6⟩ What is the SQL*Plus?

SQL*Plus is an application that recognizes & executes SQL commands & specialized SQL*Plus commands that can customize reports, provide help & edit facility & maintain system variables.

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8⟩ What is sql Correlated Subquery?

Correlated Subquery is a subquery that is evaluated once for each row processed by the parent statement. Parent statement can be Select, Update or Delete. Use CRSQ to answer multipart questions whose answer depends on the value in each row processed by parent statement.

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9⟩ What is sql Sequences?

Sequences are used for generating sequence numbers without any overhead of locking. Drawback is that after generating a sequence number if the transaction is rolled back, then that sequence number is lost.

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10⟩ What is sql Commit?

Commit is an event that attempts to make data in the database identical to the data in the form. It involves writing or posting data to the database and committing data to the database. Forms check the validity of the data in fields and records during a commit. Validity check are uniqueness, consistency and db restrictions.

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11⟩ What is sql Savepoint?

Savepoint is a point within a particular transaction to which you may rollback without rolling back the entire transaction.

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12⟩ What is sql Locking?

Locking are mechanisms intended to prevent destructive interaction between users accessing data. Locks are used to achieve.

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17⟩ What is sql Synonyms?

Synonyms is the alias name for table, views, sequences & procedures and are created for reasons of Security and Convenience.

Two levels are Public - created by DBA & accessible to all the users. Private - Accessible to creator only. Advantages are referencing without specifying the owner and Flexibility to customize a more meaningful naming convention.

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19⟩ What is sql Posting?

Posting is an event that writes Inserts, Updates & Deletes in the forms to the database but not committing these transactions to the database.

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