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This article mainly explains how PHP database executes more than one SQL command at a time. Interested friends may wish to take a look. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn how PHP database executes more than one SQL command at a time.

In the last article, we introduced the commonly used functions to obtain the query results of SQL. Different functions are used to query the data in different forms. Running the mysqli_query () function can only execute one SQL command at a time. In PHP, there is a function that allows the code to execute multiple SQL commands at a time, that is, the mysqli_multi_query () function. Next, let's take a look at the mysqli_multi_query () function.

Mysqli_multi_query () function

When running the mysqli_query () function we introduced earlier, we can only execute one SQL command at a time, but when we want to execute more than one SQL command, the mysqli_query () function cannot satisfy us, so we need to execute more than one SQL command at a time through the mysqli_multi_query () function.

The syntax format of the mysqli_multi_query () function is as follows:

Mysqli::multi_query (string $query)

This is an object-oriented approach, and here is a process-oriented approach:

Mysqli_multi_query (mysqli $link, string $query)

Among them, it should be noted that:

$query is represented as the SQL statement to be queried

$link represents the link ID returned by using the mysqli_connect () function

Query represents parameters, which can contain multiple SQL commands, each separated by a semicolon;. If the first SQL command is executed without an error, the function returns TRUE, otherwise it returns FALSE.

Next, let's take a look at the use of the mysqli_multi_query () function through an example to execute multiple SQL commands, as shown below:

Output result:

The above result completes the execution of multiple SQL commands through the mysqli_multi_query () function.

One of the things we need to pay attention to is:

Because the mysqli_multi_query () function can connect to execute one or more queries, and each SQL command may return a result, you need to get each result set if necessary. So there are some changes in the processing of the results returned by this function, and the results of the first query command are read using the mysqli_use_result () or mysqli_store_result () function.

You can also use the mysqli_store_result () function to fetch all the results back to the client immediately, and it's more efficient to do so. In addition, you can use the mysqli_more_results () function to check if there are other result sets.

If you want to process the next result set, you can use the mysqli_next_result () function to get the next result set, which returns TRUE when there is a next result set and FALSE if there is no result set. If there is a next result set, you also need to use the mysqli_use_result () or mysqli_store_result () function to read the contents of the result set.

The above uses an object-oriented approach. Next, let's take a look at the process-oriented approach. Examples are as follows:

The output is the same as above, so we complete multiple SQL commands at one time through the mysqli_multi_query () function.

At this point, I believe you have a deeper understanding of "how PHP database executes more than one SQL command at a time". You might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

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