dawei
1. false ：0 true 1 切记
官方文档：http://dev.mysql.com/doc/refman/5.0/en/numeric-type-overview.html
- ,
. A value of zero is considered false. Nonzero values are considered true:
mysql (,,
(,)
false
(,
(,)
true
(,
(,)
true
andare merely aliases forand,respectively,as shown here:
mysql ( FALSE,
( FALSE,)
true
( TRUE,
( TRUE,)
true
( TRUE,
( TRUE,)
false
( FALSE,
( FALSE,)
false
is equal to neithernor.
2 存储过程中执行动态sql
官方文档：
http://dev.mysql.com/doc/refman/5.0/en/sql-syntax-prepared-statements.html
The first example shows how to create a prepared statement by using a string literal to supply the text of the statement:
mysql stmt1 stmt1 USING ,
hypotenuse
mysql stmt1;
The second example is similar,but supplies the text of the statement as a user variable:
mysql stmt2 stmt2 USING ,
hypotenuse
mysql stmt2;
Here is an additional example which demonstrates how to choose the table on which to perform a query at runtime,by storing the name of the table as a user variable:
mysql t1 (a t1 (),(),(),(),(mysql<span style="color: #808080;">> <span style="color: #0000ff;">SET <span style="color: #008000;">@table <span style="color: #808080;">= <span style="color: #ff0000;">'<span style="color: #ff0000;">t1<span style="color: #ff0000;">'<span style="color: #000000;">;
mysql<span style="color: #808080;">> <span style="color: #0000ff;">SET <span style="color: #008000;">@s <span style="color: #808080;">= CONCAT(<span style="color: #ff0000;">'<span style="color: #ff0000;">SELECT * FROM <span style="color: #ff0000;">',<span style="color: #008000;">@table<span style="color: #000000;">);
mysql<span style="color: #808080;">> <span style="color: #0000ff;">PREPARE stmt3 <span style="color: #0000ff;">FROM <span style="color: #008000;">@s<span style="color: #000000;">;
mysql<span style="color: #808080;">> <span style="color: #0000ff;">EXECUTE<span style="color: #000000;"> stmt3;
<span style="color: #808080;">+<span style="color: #008080;">--<span style="color: #008080;">--+
<span style="color: #808080;">| a <span style="color: #808080;">|
<span style="color: #808080;">+<span style="color: #008080;">--<span style="color: #008080;">--+
<span style="color: #808080;">| <span style="color: #800000; font-weight: bold;">4 <span style="color: #808080;">|
<span style="color: #808080;">| <span style="color: #800000; font-weight: bold;">8 <span style="color: #808080;">|
<span style="color: #808080;">| <span style="color: #800000; font-weight: bold;">11 <span style="color: #808080;">|
<span style="color: #808080;">| <span style="color: #800000; font-weight: bold;">32 <span style="color: #808080;">|
<span style="color: #808080;">| <span style="color: #800000; font-weight: bold;">80 <span style="color: #808080;">|
<span style="color: #808080;">+<span style="color: #008080;">--<span style="color: #008080;">--+
<span style="color: #000000;">
mysql<span style="color: #808080;">> <span style="color: #0000ff;">DEALLOCATE <span style="color: #0000ff;">PREPARE stmt3;
总结：
执行动态sql，分三步走：
1. PREPARE；
Syntax：
stmt_name FROM preparable_stmt
2. EXECUTE；
Syntax：
stmt_name [USING @var_name [,@var_name] ...]
3. DEALLOCATE PREPARE；
Syntax：
stmt_name
3. 存储过程中的事务
语法：
START
CHAIN] CHAIN] autocommit { }
