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Legal Studies如何在不用 MySQL 中的“select from”检查表是否存在？
我们可以借助 SHOW 命令来实现此目的。首先，我将借助 USE 命令使用我的数据库 −
mysql> USE business; Database changed
我们现在位于“business”数据库中。接下来，我们可以检查此数据库中有多少个可用的表。查询如下 −
mysql> SHOW tables;
输出如下
+------------------------+ | Tables_in_business | +------------------------+ | addcolumntable | | autoincrement | | autoincrementtable | | bookindexes | | chardemo | | clonestudent | | columnvaluenulldemo | | dateadddemo | | deletedemo | | deleterecord | | demo | | demo1 | | demoascii | | demoauto | | demobcrypt | | demoemptyandnull | | demoint | | demoonreplace | | demoschema | | distinctdemo | | duplicatebookindexes | | duplicatefound | | employeetable | | existsrowdemo | | findandreplacedemo | | firsttable | | foreigntable | | foreigntabledemo | | groupdemo | | groupdemo1 | | incasesensdemo | | int1demo | | intdemo | | latandlangdemo | | limitoffsetdemo | | milliseconddemo | | modifycolumnnamedemo | | modifydatatype | | moneydemo | | moviecollection | | mytable | | nonasciidemo | | nthrecorddemo | | nulldemo | | nullwithselect | | pasthistory | | presenthistory | | primarytable | | primarytable1 | | primarytabledemo | | rownumberdemo | | rowstranspose | | rowstransposedemo | | secondtable | | sequencedemo | | smallintdemo | | spacecolumn | | student | | tblfirst | | tblstudent | | tbluni | | textdemo | | texturl | | trailingandleadingdemo | | transcationdemo | | unsigneddemo | | updtable | | varchardemo | | varchardemo1 | | varchardemo2 | | varcharurl | | whereconditon | +------------------------+ 72 rows in set (0.03 sec)
以下为我们可以在不使用 SELECT 语句的情况下检查一个表是否存在的方法。
语法如下 −
SHOW tables like ‘yourTableName’;
现在，我应用上述查询以检查表是否存在于我的数据库“business”中。
查询如下 −
mysql> SHOW tables like 'tblstudent';
输出如下
+---------------------------------+ | Tables_in_business (tblstudent) | +---------------------------------+ | tblstudent | +---------------------------------+ 1 row in set (0.00 sec)
请查看以上输出，我的数据库中可见表 ‘tblstudent’。当表不存在时的案例如下 −
mysql> SHOW tables like 'sampledemo'; Empty set (0.00 sec)
更新于： 25-6 月-2020
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