What is NVL in SQL with example?

What is NVL in SQL with example?

NVL lets you replace null (returned as a blank) with a string in the results of a query. If expr1 is null, then NVL returns expr2 . If expr1 is not null, then NVL returns expr1 .

How NVL is used in SQL?

NVL(expr1, expr2) : In SQL, NVL() converts a null value to an actual value. Data types that can be used are date, character and number. Data type must match with each other i.e. expr1 and expr2 must of same data type.

What are NVL functions?

NVL. The NVL function allows you to replace null values with a default value. If the value in the first parameter is null, the function returns the value in the second parameter. If the first parameter is any value other than null, it is returned unchanged.

How does SQL Loader handle NULL columns?

The SQL*Loader Control File

  1. the action ( LOAD DATA)
  2. the file containing the data (INFILE)
  3. the table to load into.
  4. The delimiter used in the file (FIELDS TERMINATED BY)
  5. treat any missing values at the end of a line as null (TRAILING NULLCOLS)

What is NVL and nvl2 in SQL?

Nvl(arg1,arg2) nvl is used for converting null values. In nvl if argument 1 is null then it returns argument 2 but argument 1 is not null it returns itself. In nvl2 (arg1,arg2,arg3) in nvl2 it converts any number into according to given number with null also .

How Tkprof will help to increase the performance?

The SORT value causes TKPROF to sort the SQL statements in order of the sum of the CPU time spent executing and the CPU time spent fetching rows before writing them to the output file. For greatest efficiency, always use SORT parameters.

What is NVL and NVL2 in SQL?

What is trailing Nullcols in SQL Loader?

The TRAILING NULLCOLS clause tells SQL*Loader to treat any relatively positioned columns that are not present in the record as null columns. See Handling Short Records with Missing Data. The remainder of the control file contains the field list, which provides information about column formats in the table being loaded.

What is NVL and nvl2 function and difference?

Answer: The nvl function only has two parameters while the nvl parameter has three arguments. The nvl2 like like combining an nvl with a decode because you can transform a value: NVL ( expr1 , expr2 ): If expr1 is null, then NVL returns expr2. If expr1 is not null, then NVL returns expr1.

How do you use Tkprof?

Follow these steps to use the SQL Trace facility and TKPROF :

  1. Set initialization parameters for trace file management.
  2. Enable the SQL Trace facility for the desired session, and run the application.
  3. Run TKPROF to translate the trace file created in Step 2 into a readable output file.

How do I run a Tkprof command?

Oracle : TKPROF simple steps

  1. Set the following parameters. TIMED_STATISTICS = TRUE.
  2. Enable SQL TRACE for a session. alter session set SQL_TRACE true;
  3. Run the query.
  4. obtain the number included in the trace filename.
  5. Run TKPROF at the command line to put the TRACE file into readable format.

What is NVL in Oracle SQL Server?

SQL NVL. The SQL NVL function is used to replace NULL value with an alternate value in Oracle. It’s similar to MS SQL Server’s ISNULL Function and mySQL’s IFNULL Function. NVL(exp1, exp2) If exp1 is null, the NVL function will return exp2, otherwise it will return exp1.

How do you use nvl2 function?

NVL2 (expr1, expr2, expr3) : The NVL2 function examines the first expression. If the first expression is not null, then the NVL2 function returns the second expression. If the first expression is null, then the third expression is returned i.e. If expr1 is not null, NVL2 returns expr2. If expr1 is null, NVL2 returns expr3.

What is the use of lnnvl in SQL?

LNNVL () : LNNVL evaluate a condition when one or both operands of the condition may be null. The function can be used only in the WHERE clause of a query. It takes as an argument a condition and returns TRUE if the condition is FALSE or UNKNOWN and FALSE if the condition is TRUE.

What is the syntax of the NVL () function?

The following shows the syntax of the NVL () function: The NVL () function accepts two arguments. If e1 evaluates to null, then NVL () function returns e2. If e1 evaluates to non-null, the NVL () function returns e1. The two arguments e1 and e2 can have the same or different data types.