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To make MySQL compatible with some ODBC applications, you can find the AUTO_INCREMENT value for the last inserted row with the following query: SELECT * FROM tbl_name WHERE auto_col IS NULL. This is done with a special code that replaces 'auto_col IS NULL' with 'auto_col = LAST_INSERT_ID'. However this also resets the LAST_INSERT_ID to 0 as it uses it for a flag so as to ensure that only the first SELECT ... WHERE auto_col IS NULL after an INSERT has this special behaviour. In order to avoid resetting the LAST_INSERT_ID a special flag is introduced in the THD class. This flag is used to restrict the second and subsequent SELECTs instead of LAST_INSERT_ID. mysql-test/r/odbc.result: test suite for the bug mysql-test/r/rpl_insert_id.result: test for the fix in replication mysql-test/t/odbc.test: test suite for the bug mysql-test/t/rpl_insert_id.test: test for the fix in replication sql/sql_class.cc: initialize the flag sql/sql_class.h: flag's declaration and set code when setting the last_insert_id sql/sql_select.cc: the special flag is used instead of last_insert_id
27 lines
915 B
Text
27 lines
915 B
Text
drop table if exists t1;
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select {fn length("hello")}, { date "1997-10-20" };
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{fn length("hello")} 1997-10-20
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5 1997-10-20
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create table t1 (a int not null auto_increment,b int not null,primary key (a,b));
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insert into t1 SET A=NULL,B=1;
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insert into t1 SET a=null,b=2;
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select * from t1 where a is null and b=2;
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a b
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2 2
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select * from t1 where a is null;
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a b
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explain select * from t1 where b is null;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
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drop table t1;
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CREATE TABLE t1 (a INT AUTO_INCREMENT PRIMARY KEY);
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INSERT INTO t1 VALUES (NULL);
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SELECT sql_no_cache a, last_insert_id() FROM t1 WHERE a IS NULL;
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a last_insert_id()
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1 1
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SELECT sql_no_cache a, last_insert_id() FROM t1 WHERE a IS NULL;
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a last_insert_id()
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SELECT sql_no_cache a, last_insert_id() FROM t1;
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a last_insert_id()
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1 1
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DROP TABLE t1;
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