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https://dev.mysql.com/doc/refman/8.0/en/json-search-functions.html
row *************************** id: 1 select_type: SIMPLE table: jemp partitions: NULL type: range possible_keys: i key: i key_len: 5 ref: NULL rows: 2 filtered: 100.00 Extra: Using where 1 row in set, 1 warning (0.00 sec) mysql> SHOW WARNINGS\G ...
https://dev.mysql.com/doc/refman/8.0/en/insert-on-duplicate.html
If you specify an ON DUPLICATE KEY UPDATE clause and a row to be inserted would cause a duplicate value in a UNIQUE index or PRIMARY KEY, an UPDATE of the old row occurs. If column b is also unique, the INSERT is equivalent to this UPDATE statement ...In general, you should try to avoid using an ON DUPLICATE KEY UPDATE clause on tables with multiple unique ...
https://dev.mysql.com/doc/refman/8.0/en/partitioning-selection.html
Explicit selection of partitions and subpartitions for rows matching a given WHERE condition is supported. When the PARTITION option is used, only the partitions and subpartitions listed are checked for matching rows. This option can be used in a ...Partition selection is similar to partition pruning, in that only specific partitions are checked for matches, but differs in two key respects: The partitions to be checked are specified by the issuer of the statement, unlike partition pruning, which is ...
https://dev.mysql.com/doc/refman/8.0/en/set-operations.html
INTERSECT: Combine only those rows which the results of two query blocks have in common, omitting any duplicates. In other words, all of the following statements are true: TABLE x UNION TABLE y and TABLE y UNION TABLE x produce the same result, ...
https://dev.mysql.com/doc/refman/8.0/en/sql-mode.html
For a nontransactional table, abort the statement if the value occurs in a single-row statement or the first row of a multiple-row statement. A value is missing when a new row to be inserted does not contain a value for a non-NULL column that has no ... The MySQL server can operate in different SQL modes, and can apply these modes differently for different clients, depending on the value of the sql_mode system ...
https://dev.mysql.com/doc/refman/8.0/en/replace.html
| VALUES row_constructor_list } REPLACE [LOW_PRIORITY | DELAYED] [INTO] tbl_name [PARTITION (partition_name [, partition_name] ...)] SET assignment_list REPLACE [LOW_PRIORITY | DELAYED] [INTO] tbl_name [PARTITION (partition_name [, partition_name] ... REPLACE [LOW_PRIORITY | DELAYED] [INTO] tbl_name [PARTITION (partition_name [, partition_name] ...)] [(col_name [, col_name] ...)] { {VALUES | VALUE} (value_list) [, (value_list)] ...
https://dev.mysql.com/doc/refman/8.0/en/innodb-locks-set.html
It does not matter whether there are WHERE conditions in the statement that would exclude the row. If you have no indexes suitable for your statement and MySQL must scan the entire table to process the statement, every row of the table becomes ... A ...
https://dev.mysql.com/doc/refman/8.0/en/nested-join-optimization.html
In some of the following examples, NULL where a table name appears means a row in which NULL is used for each column of that table. For example, t1||t2||NULL indicates a row constructed by concatenating the columns of rows t1 and t2, and NULL for ...
https://dev.mysql.com/doc/refman/8.0/en/xml-functions.html
row *************************** val1: <e>fff</e> val2: <a><b>ccc</b><d></d></a> val3: <a><e>fff</e><d></d></a> val4: <a><b>ccc</b><e>fff</e></a> val5: <a><d></d><b>ccc</b><d></d></a> Note A discussion in depth of XPath syntax and usage are beyond ...
https://dev.mysql.com/doc/refman/8.0/en/condition-filtering.html
In join processing, prefix rows are those rows passed from one table in a join to the next. In general, the optimizer attempts to put tables with low prefix counts early in the join order to keep the number of row combinations from increasing ...A ...