MySQL 中 = 和 := 的区别
Difference between = and := in MySQL
在MySQL这两个命令有什么区别？
它们工作得很好，结果总是一样的：
set @numRecords = (select count(*) from config);
set @numRecords := (select count(*) from config);
谢谢
大卫
引用 MySQL 5.7 参考手册，section 10.4 User-Defined Variables:
For SET, either = or := can be used as the assignment operator.
You can also assign a value to a user variable in statements other
than SET. In this case, the assignment operator must be := and not =
because the latter is treated as the comparison operator = in non-SET
statements
"=" 不明确，可能是比较运算符。 “:=”总是被解释为赋值运算符。此信息可在 http://dev.mysql.com/doc/refman/5.7/en/assignment-operators.html .
中找到
在MySQL这两个命令有什么区别？
它们工作得很好，结果总是一样的：
set @numRecords = (select count(*) from config);
set @numRecords := (select count(*) from config);
谢谢 大卫
引用 MySQL 5.7 参考手册，section 10.4 User-Defined Variables:
For SET, either = or := can be used as the assignment operator.
You can also assign a value to a user variable in statements other than SET. In this case, the assignment operator must be := and not = because the latter is treated as the comparison operator = in non-SET statements
"=" 不明确，可能是比较运算符。 “:=”总是被解释为赋值运算符。此信息可在 http://dev.mysql.com/doc/refman/5.7/en/assignment-operators.html .
中找到