to the requirements of individual applications. For information on how to require users to use encrypted connections, see the discussion of theREQUIREclause of theCREATE USERstatement inCREATE USER Statement. Se
If the result of a string operation on an INFORMATION_SCHEMA column differs from expectations, a workaround is to use an explicit COLLATE clause to force a suitable collation (see Section 1.8.1, “Using COLLATE in SQL Statements”). For example, to perform a case-insensitive search, use COL...
官方的定义是,MySQLmust do an extra pass to find out how to retrieve the rows in sorted order. The sort is done by going through all rows according to the join type and storing the sort key and pointer to the row for all rows that match the WHERE clause . The keys then are sorted ...
alias 'Name' as it has been renamed by the query. ***NOTE*** This query returns the correct column name: SELECT Description AS Name FROM test LEFT JOIN tblTest2 ON test.Test_ID = tblTest2.Test_ID; It appears that the bug is specific to the USING clause in combination with a VIEW....
http://dev.mysql.com/doc/mysql/en/EXPLAIN.html You could try it with both cha.unitid = 1 and cha.unitid IN(1) and see what differences there are. -- Nick Roper Subject Views Written By Posted Using "IN" in the WHERE clause ...
A WHERE clause is used to restrict which rows to match against the next table or send to the client. Unless you specifically intend to fetch or examine all rows from the table, you may have something wrong in your query if the Extra value is not Using where and the table join type is...
A WHERE clause is used to restrict which rows to match against the next table or send to the client. Unless you specifically intend to fetch or examine all rows from the table, you may have something wrong in your query if the Extra value is not Using where and the table join type is...
A WHERE clause is used to restrict which rows to match against the next table or send to the client. Unless you specifically intend to fetch or examine all rows from the table, you may have something wrong in your query if the Extra value is not Using where and the table join type ...
To resolve the query, MySQL needs to create a temporary table to hold the result. This typically happens if the query containsGROUP BYandORDER BYclauses that list columns differently. 为了解析查询,MySQL 需要创建一个临时表来保存结果,如果查询包含以不同方式列出列的 GROUP BY 和 ORDER BY 子句,通...
It seems that using "IN" clauses with composite values, does not use any of the indexes that might exist for the individual keys. For example: SELECT * from foobar where (`field1`,`field2`) IN (('a',1) , ('b',2) ...) ...