1、id的含义 The SELECT identifier. This is the sequential number of the SELECT within the query. The value can be NULL if the row refers to the union result of other rows. In this case, the table column shows a value like <unionM,N> to indicate that the row refers to the union of...
MySQL explains how it would process the statement, including information about how tables are joined and in which order. For information about using EXPLAIN to obtain execution plan information, see Section 8.8.2, “EXPLAIN Output Format”. 当...
{explainable_stmt|FORCONNECTION connection_id} {EXPLAIN|DESCRIBE|DESC} ANALYZE select_statement explain_type: { FORMAT=format_name } format_name: { TRADITIONAL|JSON|TREE } explainable_stmt: {SELECTstatement|TABLEstatement|DELETEstatement|INSERTstatement|REPLACE statement|UPDATEstatement } 示例: EXPLAIN fo...
Herein, the box represents a set and the books represent the elements of the set. If the box is empty then it represents a null set.Answer and Explanation: The statement D⊂B implies that all the elements which are included ...
Explain the following statement: There is no such thing as a free lunch in relation to scarce resources. Trade-Off: One of the fundamentals problems in economics is the problem of scarce resources. As resources are limited, our unlimited wants cannot be ...
statement, $2.explain_into_variable_name.length ? std::optional<std::string_view>( to_string_view($2.explain_into_variable_name)) : std::optional<std::string_view>(std::nullopt), $3.schema_name_for_explain); } ; describe_command 语义组用于解析 DESCRIBE、EXPLAIN 和DESC 关键字,详见...
4 If his statement does not throw light on the subject, heA can explain the subject clearlyB can hardly make himself understood concenin on the subject5 If the emperor was very cruel to his people, he___A treated his people kindlyB...
完全相同,适用于PreparStatement -预防SQL注入攻击 何为注入攻击: 用户输入了含有SQL成分的参数,参数在拼接SQL时造成SQL语句的语义改变!进一步改变SQL语句的执行计划!最终的执行...一样的时候才重用相同的执行计划-如果SQL语句中有一个字符的更改,也会执行不同的执行计划-SQL中一个空格或者一个大小写不同也会创建不...
| 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, ...
I can't explain such a statement by him on the basis of logic. He must have blown his top. 我从逻辑推理方面解释不了他讲的这番话,他想必是神经错乱了. 《现代汉英综合大词典》 He will explain it fully once and for all. 他将把它充分地解释一次就此了结. 《简明英汉词典》 Many theories pur...