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分享简单的mysql数据select问题？
mysql数据库，有四张表，表名为,a1,a2,a3,a4,四个表中都有字段test,yeardate,现在我想把四张表中test字段前三位为123同时yeardata字段为2002的数据取出来，该怎么写sql语句？两个字段都为varchar类型，谢谢！
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lxf_1976 2003-09-10
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需要使用union语句，例如：
SELECT test, yeardate FROM a1 WHERE test like '123%' AND yeardata='2002'
UNION
SELECT test, yeardate FROM a2 WHERE test like '123%' AND yeardata='2002'
UNION
SELECT test, yeardate FROM a3 WHERE test like '123%' AND yeardata='2002'
UNION
SELECT test, yeardate FROM a4 WHERE test like '123%' AND yeardata='2002'
SELECT test, yeardate FROM a1 WHERE test like '123%' AND yeardata='2002'
UNION
SELECT test, yeardate FROM a2 WHERE test like '123%' AND yeardata='2002'
UNION
SELECT test, yeardate FROM a3 WHERE test like '123%' AND yeardata='2002'
UNION
SELECT test, yeardate FROM a4 WHERE test like '123%' AND yeardata='2002'
