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https://dev.mysql.com/doc/c-api/8.4/en/mysql-stmt-error.html
const char * mysql_stmt_error(MYSQL_STMT *stmt) Description For the statement specified by stmt, mysql_stmt_error() returns a null-terminated string containing the error message for the most recently invoked statement API function that can succeed ...Either of these two tests can be used to check for an error: if(*mysql_stmt_errno(stmt)) { // an error occurred } if (mysql_stmt_error(stmt)[0]) { // an error occurred } If the failed statement API function was mysql_stmt_close(), do not call mysql_stmt_error() to obtain error information because mysql_stmt_close() makes the statement handler ...
https://dev.mysql.com/doc/refman/8.4/en/any-in-some-subqueries.html
The expression is unknown (that is, NULL) if table t2 contains (NULL,NULL,NULL). The expression is TRUE if table t2 contains (21,14,7) because there is a value 7 in t2 that is less than 10. The expression is FALSE if table t2 contains (20,10), or if ...
https://dev.mysql.com/doc/refman/8.4/en/explain-extended.html
row *************************** id: 1 select_type: PRIMARY table: t1 type: index possible_keys: NULL key: PRIMARY key_len: 4 ref: NULL rows: 4 filtered: 100.00 Extra: Using index *************************** 2. row *************************** id: 2 ... The EXPLAIN statement produces extra (“extended”) information that is not part of EXPLAIN output but can be viewed by issuing a SHOW WARNINGS statement following ...
https://dev.mysql.com/doc/refman/8.4/en/index-page-merge-threshold.html
row *************************** Table: t2 Create Table: CREATE TABLE `t2` ( `id` int(11) DEFAULT NULL, KEY `id_index` (`id`) COMMENT 'MERGE_THRESHOLD=40' ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci Note A MERGE_THRESHOLD value ...If the “page-full” percentage for an index page falls below the MERGE_THRESHOLD value when a row is deleted or when a row is shortened by an UPDATE operation, InnoDB attempts to merge the index page with a neighboring index ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-limitations-syntax.html
Attempting to create an index on an NDB table column whose width is greater than 3072 bytes is rejected with ER_TOO_LONG_KEY: Specified key was too long; max key length is 3072 bytes. Attempting to create an index on an NDB table column whose width ... Some SQL statements relating to certain MySQL features produce errors when used with NDB tables, as described in the following list: Temporary ...
https://dev.mysql.com/doc/refman/8.4/en/show-warnings.html
mysql> CREATE TABLE t1 (a TINYINT NOT NULL, b CHAR(4)); Query OK, 0 rows affected (0.05 sec) mysql> INSERT INTO t1 VALUES(10,'mysql'), (NULL,'test'), (300,'xyz'); Query OK, 3 rows affected, 3 warnings (0.00 sec) Records: 3 Duplicates: 0 Warnings: 3 ... SHOW WARNINGS [LIMIT [offset,] row_count] SHOW COUNT(*) WARNINGS SHOW WARNINGS is a diagnostic statement that displays information about the conditions (errors, warnings, and notes) resulting from executing a statement in the current ...
https://dev.mysql.com/doc/refman/8.4/en/optimizer-statistics.html
Here is a sample histogram object: { "buckets": [ [ 1, 0.3333333333333333 ], [ 2, 0.6666666666666666 ], [ 3, 1 ] ], "null-values": 0, "last-updated": "2017-03-24 13:32:40.000000", "sampling-rate": 1, "histogram-type": "singleton", ... The ...
https://dev.mysql.com/doc/refman/8.4/en/date-and-time-literals.html
Standard SQL and ODBC Date and Time Literals String and Numeric Literals in Date and Time Context Date and time values can be represented in several formats, such as quoted strings or as numbers, depending on the exact type of the value and other ...For example, in contexts where MySQL expects a date, it interprets any of '2015-07-21', '20150721', and 20150721 as a ...
https://dev.mysql.com/doc/heatwave-aws/en/heatwave-aws-user-configurable-system-variables.html
User-Configurable System Variables 19.5 User-Configurable System Variables Configure the following global system variables with the MySQL HeatWave Console. Note:Click on the name of a system varuable in Table 19-7 to see its description in the ...
https://dev.mysql.com/doc/connectors/en/connector-j-usagenotes-statements.html
Once you have a Statement instance, you can execute a SELECT query by calling the executeQuery(String) method with the SQL you want to use. To update data in the database, use the executeUpdate(String SQL) method. If you do not know ahead of time ...