How to Use the EXPLAIN Keyword in MySQL EXPLAINin MySQL is a powerful tool used to analyze and understand how MySQL executes a particular query. Here’s whatEXPLAINcan do: Display the query execution plan: EXPLAIN shows how MySQL intends to execute a query, including the order of data retrie...
The DESCRIBE and EXPLAIN statements are synonyms. In practice, the DESCRIBE keyword is more often used to obtain information about table structure, whereas EXPLAIN is used to obtain a query execution plan (that is, an explanation of how MySQL would execute a query). URL: http://dev.mysql.co...
(1)When youprecede a SELECT statement with the keyword EXPLAIN, MySQL displays informationfrom the optimizer about the query execution plan. That is, MySQL explains howit would process the statement, including information about how tables are joinedand in which order. EXPLAIN EXTENDED can be used ...
(1)WhenyouprecedeaSELECTstatementwiththekeywordEXPLAIN,MySQLdisplaysinformationfromtheoptimizeraboutthequeryexecutionplan.Thatis,MySQLexplainshowitwouldprocessthestatement,includinginformationabouthowtablesarejoinedandinwhichorder.EXPLAINEXTENDEDcanbeusedtoprovideadditionalinformation. ...
In older MySQL releases, partition information was produced usingEXPLAIN PARTITIONS. That syntax is still recognized for backward compatibility but partition output is now enabled by default, so thePARTITIONSkeyword is superfluous and deprecated. Its use results in a warning, and it is removed fromEXP...
1 row in set (0.00 sec) 一.OptimizingQueries with EXPLAIN The EXPLAINstatement can be used either as a way to obtain information about how MySQLexecutes a statement, or as a synonym for DESCRIBE: (1)When youprecede a SELECT statement with the keyword EXPLAIN, MySQL displays informationfrom ...
.. The DESCRIBE and EXPLAIN statements are synonyms. In practice, the DESCRIBE keyword is more often used to obtain information about table structure, whereas EXPLAIN is used to obtain a query execution plan (that is, an explanation of how MySQL would execute a query). ...
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o When you precede a SELECT statement with the keyword EXPLAIN, MySQL displays information from the optimizer about the query execution plan. That is, MySQL explains how it would process the statement, including information about how tables are joined and in which order. ...
([t2.c2], [t2.c1]), filter(nil), access([t2.c2], [t2.c1]), partitions(p0) 2 - output([t1.c2], [t1.c1]), filter(nil), access([t1.c2], [t1.c1]), partitions(p0) Use the EXTENDED_NOADDR keyword to output additional information in the execution plan. obclient> ...