Tips for using the decode () function in Oracle

I. Software Environment

1. windows nt4.0 + oracle 8.0.4

2. oracle installation path: c: \ orant

Ii. Meaning

 

Iii. Usage

1. Compare the size

Select decode (sign (variable 1-variable 2),-1, variable 1, variable 2) from dual; -- smaller value

The sign () function returns 0, 1, and-1 respectively based on a value of 0, positive, or negative.

For example:

Variable 1 = 10, variable 2 = 20

Then sign (variable 1-variable 2) returns-1, and the decode decoding result is "variable 1", achieving the goal of getting a smaller value.

2. Table and View Structure Conversion

There is a sales table sale with the following structure:

 

Data to be converted to the following structure:

 

The SQL statement for structure conversion is:

 

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