1. For date type data, do *,/operation is not legal 2. The value of a mathematical expression that contains null values is a null value of 3. Aliases can add keywords ' as ' between column names and aliases, using double quotation marks to include spaces or special characters in the alias and case sensitivity 4. The connection string in Oracle uses "| |" instead of "+" 5 in Java. Dates and characters can only appear in single quotation marks. Output last_name ' s email is email 6. Distinct keyword, the following syntax error: Select Last_Name, distinct DEPARTMENT_IDFROM employees 7. SQL statement with sql*plus command SQL
- A language
- ANSI Standard
- Keywords cannot be abbreviated
- Use statements to control the definition information of tables in a database and the data in a table
Sql*plus
- An environment
- One of the features of Oracle
- Keywords can be abbreviated
- Command cannot change the value of data in a database
- Centralized operation
Use Sql*plus to:
- Describes the table structure.
- Edit the SQL statement.
- Executes the SQL statement.
- Save SQL in a file and save the results of the SQL statement execution in a file.
- Executes the statement in the saved file.
- Loads a text file into the Sql*plus edit window.
DAY01 Basic SQL SELECT
