Category: Oracle PL SQL

Learn about NULL value and an empty string behavior in oracle database with example queries. NULL means no-value(nothing). An empty string(”) treated as NULL value

Learn the about the logical columns that are not exist in the table, but how can be used to select the data from the table,

Learn about the logical columns that exists in oracle database with example queries. Pseudo columns are nothing but logical columns which behaves like a physical

Learn how to identify the columns present with NULL values in the table with example queries. There can be different ways to identify the columns

Learn how to remove duplicate records present in a table with standard sql queries and also dynamic sql with example queries. For base table reference

Learn how to fetch top N rows using SQL TOP, ROWNUM, LIMIT, FETCH clauses with example queries. Row Limiting clause is useful to limit the

Learn how to write SQL queries for questions given below. Queries are based on the Employee and Incentives tables given below. Let’s prepare the both

Learn how to extract a DAY,MONTH,YEAR,HOUR,MINUTE AND SECOND from a date time data type values. EXTRACT function extracts a date or a timestamp and returns

Learn how to use a Time stamp data type ,how to convert a Time stamp in string format to a string Timestamp format using TO_TIMESTAMP

Learn how to convert a date in string format to a string Date format using TO_DATE function and Date literal formats. Also Learn how to