Several ways to get the id of the data just inserted in php

This article mainly introduces several methods for PHP to obtain the id of newly inserted data. It has certain reference value. Now I share it with you. Friends in need can refer to it.

Insert data into mysql Many times we want to know the id of the data we just inserted. This is very useful for us. Below I will talk about three commonly used methods and analyze their advantages and disadvantages one by one.

Use the following statement:

mysql_query("select max(id) from t1",$link);

When using this method we get The largest ID value is indeed the last one, but when there are multiple connection threads, the largest ID is not necessarily the one we inserted, so this does not use domain threads.

Second, use the following function:

msyql_insert_id();

After the system has finished executing INSERT, then When executing SELECT, it may have been distributed to different back-end servers. If the programming language you are using is PHP, you should use mysql_insert_id() to get the latest inserted id. After each INSERT ends, the corresponding autoincrement value It has been calculated and returned to PHP. You don't need to issue a separate query, just use mysql_insert_id(). This function is very useful. When we insert a statement, it automatically returns the last id value and this function is only for The current link is useful, that is to say, it is multi-user safe, so we often use this function;

But there is a problem with this function that it will no longer work when the id is of bigint type, so we are using this function now. Please be careful, but we rarely encounter such problems, so we don’t need to worry about it.

Three: Use the query

msyql_query("select last_insert_id()");

last_insert_id() is a mysql function as well Valid for the current link. This usage solves the bigint type problem encountered in mysql_insert_id ().

Summary: Based on the above analysis, use the first method as little as possible and use the second method more. When encountering special circumstances, you can consider using the third method

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