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|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...
{EXPLAIN | DESCRIBE | DESC} tbl_name [col_name | wild] {EXPLAIN | DESCRIBE | DESC} [explain_type] {explainable_stmt | FOR CONNECTION connection_id} {EXPLAIN | DESCRIBE | DESC} ANALYZE select_statement explain_type: { FORMAT = format_name} format_name: { TRADITIONAL | JSON | TREE} ex...
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...
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 ...
| UPDATE statement } 示例: EXPLAIN format = TRADITIONAL json SELECT tt.TicketNumber, tt.TimeIn, tt.ProjectReference, tt.EstimatedShipDate, tt.ActualShipDate, tt.ClientID, tt.ServiceCodes, tt.RepetitiveID, tt.CurrentProcess, tt.CurrentDPPerson, ...
SET optimizer_switch = 'index_condition_pushdown=on'; 1. 2. 开或者关闭索引条件下推,并对比: AI检测代码解析 explain SELECT * FROM people WHERE zipcode='95054' AND lastname LIKE '%etrunia%' AND address LIKE '%Main Street%'; 1.
In the first statement, value of a will be 10, because assignment operator (=) has more priority more than comma (,), thus 10 will be assigned to the variable a.In the second statement, value of b will be 30, because 10, 20, 30 are enclosed in braces, and braces has more ...
final public SqlNode SqlRichExplain() throws ParseException { SqlNode stmt; Set<String> explainDetails = new HashSet<String>(); jj_consume_token(EXPLAIN); switch ((jj_ntk==-1)?jj_ntk():jj_ntk) { case PLAN: case CHANGELOG_MODE: case ESTIMATED_COST: case JSON_EXECUTION_PLAN: switch (...