Evaluate the following SQL commands:

The command to create a table fails. Identify the reason for the SQL statement failure.

In the PROMOTIONS table, the PROMO_BEGIN_DATEcolumn is of data type DATEand the default date format is DD-MON-RR.
Which two statements are true about expressions using PROMO_BEGIN_DATEcontained a query? (Choose two.)

Which two statements are true regarding constraints?

資料を参照して、EMPLOYEES テーブルの説明を調べてください。

各従業員の合計報酬を計算したいとします。総報酬は、年間給与と年間で得られる歩合給の合計です。歩合給を得る従業員はほんのわずかです。
目的の出力を得るにはどの SQL ステートメントを実行しますか?

The customers table has the following structure:

You need to write a query that does the following tasks:
1. Display the first name and tax amount of the customers. Tax is 5% of their credit limit.
2. Only those customers whose income level has a value should be considered.
3. Customers whose tax amount is null should not be considered.
Which statement accomplishes all the required tasks?