In C#, the switch statement serves as a control structure that enables the execution of distinct code blocks based on the value of a variable. It is frequently utilized when there is a need to compare a variable with multiple constant values and to carry out various actions according to the...
{EXPLAIN|DESCRIBE|DESC}tbl_name[col_name|wild]{EXPLAIN|DESCRIBE|DESC}[explain_type]{explainable_stmt|FORCONNECTIONconnection_id}{EXPLAIN|DESCRIBE|DESC}ANALYZEselect_statementexplain_type:{FORMAT=format_name}format_name:{TRADITIONAL|JSON|TREE}explainable_stmt:{SELECTstatement|TABLEstatement|DELETEstatement|I...
当前使用了半连接LooseScan策略,详见https://mariadb.com/kb/en/loosescan-strategy/,翻译http://www.javacoder.cn/?p=39 No matching min/max row 没有任何能满足例如 SELECT MIN(…) FROM … WHERE condition 中的condition的行。 no matching row in const table 对于关联查询,存在一个空表,或者没有行...
explainable_stmt: {SELECTstatement|TABLEstatement|DELETEstatement|INSERTstatement|REPLACE statement|UPDATEstatement } 示例: EXPLAIN format=TRADITIONAL jsonSELECTtt.TicketNumber, tt.TimeIn, tt.ProjectReference, tt.EstimatedShipDate, tt.ActualShipDate, tt.ClientID, tt.ServiceCodes, tt.RepetitiveID, tt.Curr...
EXPLAIN Statement Extended EXPLAIN Output Format Estimating Query Performance MySQL中explain执行计划中额外信息字段(Extra)详解 explain参数详解 最官方的 mysql explain type 字段解读 What does eq_ref and ref types mean in MySQL explain 面试官:不会看 Explain执行计划,简历敢写 SQL 优化?
8 unique_subquery:该类型和eq_ref类似,但是使用了IN查询,且子查询是主键或者唯一索引。例如: value IN (SELECT primary_key FROM single_table WHERE some_expr) 9 index_subquery:和unique_subquery类似,只是子查询使用的是非唯一索引 value IN (SELECT key_column FROM single_table WHERE some_expr) ...
Step 7 - If the statement is an UPDATE or INSERT, it is passed to the transaction manager for further processing. Step 8 - During a transaction, the data is in lock mode. This is guaranteed by the lock manager. It also ensures the transaction’s ACID properties. ...
explain_type:{FORMAT=format_name}format_name:{TRADITIONAL|JSON|TREE}explainable_stmt:{SELECTstatement|TABLEstatement|DELETEstatement|INSERTstatement|REPLACEstatement|UPDATEstatement} 示例: EXPLAINformat=TRADITIONALjsonSELECTtt.TicketNumber,tt.TimeIn,tt.ProjectReference,tt.EstimatedShipDate,tt.ActualShipDate,tt...
SET optimizer_switch = 'index_condition_pushdown=off'; SET optimizer_switch = 'index_condition_pushdown=on'; 开或者关闭索引条件下推,并对比: explain SELECT * FROM people WHERE zipcode='95054' AND lastname LIKE '%etrunia%' AND address LIKE '%Main Street%'; 的执行结果。 index condition ...
SqlExplainFormat类属于org.apache.calcite.sql包,在下文中一共展示了SqlExplainFormat类的15个代码示例,这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞,您的评价将有助于系统推荐出更棒的Java代码示例。 示例1: trimUnusedFields