从meta_key MySQL中删除meta_values

Question

我在MySQL中非常糟糕，我需要在表格中将值first_name和last_name更新为空白。我试图做这样的事情：

DELETE FROM nomtable WHERE meta_key = 'first_name' 

但我害怕弄得一团糟......

Answer 1

使用bool CTextureShader::Render(ID3D11DeviceContext* _pDeviceContext, const int _IndexCount, XMMATRIX& _pWorldMatrix, XMMATRIX& _pViewMatrix, XMMATRIX& _pProjectionMatrix, ID3D11ShaderResourceView* _pTexture) { bool result = SetShaderParameters(_pDeviceContext, _pWorldMatrix, _pViewMatrix, _pProjectionMatrix, _pTexture); if (!result) return false; RenderShader(_pDeviceContext, _IndexCount); return true; } bool CTextureShader::SetShaderParameters(ID3D11DeviceContext* _pDeviceContext, XMMATRIX& _WorldMatrix, XMMATRIX& _ViewMatrix, XMMATRIX& _ProjectionMatrix, ID3D11ShaderResourceView* _pTexture) { HRESULT result; D3D11_MAPPED_SUBRESOURCE mappedResource; MatrixBufferType* dataPtr; unsigned int bufferNumber; _WorldMatrix = XMMatrixTranspose(_WorldMatrix); _ViewMatrix = XMMatrixTranspose(_ViewMatrix); _ProjectionMatrix = XMMatrixTranspose(_ProjectionMatrix); result = _pDeviceContext->Map(m_pMatrixBuffer, 0, D3D11_MAP_WRITE_DISCARD, 0, &mappedResource); if (FAILED(result)) return false; dataPtr = (MatrixBufferType*)mappedResource.pData; dataPtr->world = _WorldMatrix; dataPtr->view = _ViewMatrix; dataPtr->projection = _ProjectionMatrix; _pDeviceContext->Unmap(m_pMatrixBuffer, 0); bufferNumber = 0; _pDeviceContext->VSSetConstantBuffers(bufferNumber, 1, &m_pMatrixBuffer); _pDeviceContext->PSSetShaderResources(0, 1, &_pTexture); return true; } void CTextureShader::RenderShader(ID3D11DeviceContext* _pDeviceContext, const int _IndexCount) { _pDeviceContext->IASetInputLayout(m_pLayout); _pDeviceContext->VSSetShader(m_pVertexShader, NULL, 0); _pDeviceContext->PSSetShader(m_pPixelShader, NULL, 0); _pDeviceContext->PSSetSamplers(0, 1, &m_pSampleState); _pDeviceContext->DrawIndexed(_IndexCount, 0, 0); } ：

UPDATE

设置为空白是什么意思：空字符串UPDATE nomtable SET meta_value = NULL -- or '' WHERE meta_key IN ('first_name', 'last_name') -- AND user_id = ?; 或''？

如果您不想更新所有值，可以添加NULL，但是对于特定用户。

Answer 2

使用Mysql 更新或尝试此查询

UPDATE nomtable
SET  meta_value = ''
WHERE meta_key ='first_name' OR meta_key ='last_name'