Creating a self-join often requires multiple join conditions.

创建自联接通常需要多个联接条件。

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But Mr Blair said he had always believed that it was important to be supportive of the project politically so the UK could join when the conditions were right "and I still think that's the case".

BBC: Tony Blair: UK may face 'interesting choice' over euro

Then they're asked to minimize these conditions and join a coalition that might not benefit them.

NPR: What Will Be African-Americans' Political Destiny?

It opted out of the single European currency, although Mr Blair says he is determined to join up when economic conditions are right.

ECONOMIST: Why Britain��s prime minster needs to change tack on Europe