Command statements and SQL statements commonly used in the Level 2 computer exam

SQL Structured Query Language is a database query and programming language for accessing data and querying, updating, and managing relational database systems. There are four levels of the exam: the first level is simple, the second level is mainly some basic programming, which also has some simple databases, and the third and fourth levels are high-level database technology.

It's useless, it's almost the same as taking a major level 3, and the rest is useless. It's the network engineer certificate.

Looking at the questions you asked, it can be seen that you are more worried about the SQL questions.

I don't know what the landlord is worried about? Ability?

If you want to take the computer level 2 exam, if you don't know SQL, I advise you not to take the test, it's meaningless.

If you make software, it's almost all about databases. If you don't know SQL, even if you pass level 2, it doesn't seem to have much effect.

select (the name of the column to be queried, * represents all) form (which table) where (whether it is type, true then run the statement before where, and the commonly used column is the conditional data to be queried).

I'm also a newbie.

For example, select column1,column2 from table1 where query conditions.

Note: This syntax is mainly used for querying, and the meaning is -- (query condition) requires the data in column1 and column2 in the table that meet the requirements from the table1 table!

The place where the column name is written can be represented by "*", which means that all the queries are made! You can also write any column name (column1, colum2 is the column name).

As for the query conditions behind where, there are many (for example, if you query students older than 18 and there is a column in the table age, you can write it as age>18) here are not examples one by one! You still have to read more books! Good luck!

Select lists from to indicate where is the condition of the query.

Create a table:

create table gz3

select statement:

select zg.Employee number, zgSalary from zg,dgd where dgd

**Trade name S7 and DGD**Trade name S4 and DGD**Trade name S6 Order by Payroll Desc

What is the second level VF of the computer?。。。

Looks like I will.

You'd better fail the course. Easy questions are also asked.

1. They are all database management systems, and the difference is still very large, access is a medium-sized database, and SQL is a large-scale database.

2. There are similarities or identical places in SQL statements.

3. There are still differences in other aspects, and you need to re-learn, but if you have a SQL foundation, access is still relatively easy to understand.

It's all about the same database, but it's better to buy a book and take a look, after all, there are still some differences, and the basic principles are almost the same.

update

Student transcripts.

SET score = score + 10

where professional ='Computers'

It depends on the structure of your table.

update

Transcripts. set

Grade = Grade + 10

whereCourse Name='Major in Computer Applications'