Oracle performance optimization operation 2: Avoid unnecessary type conversion and oracle Performance Optimization

Oracle performance optimization operation 2: Avoid unnecessary type conversion and oracle Performance Optimization

It should be noted that the potential data type conversion should be avoided as much as possible.

For example, if you compare the numeric data with the numeric data, ORACLE automatically converts the numeric data using the to_number () function, resulting in a full table scan.

Example 2: If the column col1 in tab1 is char, type conversion exists in the following statements:

<Span style = "font-size: 18px;"> select col1, col2 from tab1 where col1> 10; </span>

It should be written as follows:

<Span style = "font-size: 18px;"> select col1, col2 from tab1 where col1> '10'; </span>